Since returning to office in January 2025, the Trump administration has aggressively exercised executive authority across the federal government. Meanwhile, Congress has not adequately applied its oversight role to rein in the executive branch, particularly over the Department of Defense. We have watched these dynamics with specific interest, in discussions with congressional staff over bills and appropriations, and in conversations with our clients.
Congress adjourned at the end of September until after the midterm elections following an unproductive summer legislative session, particularly on foreign policy. While Congress passed a long-debated Russia sanctions bill in September, President Donald Trump has already issued a waiver to it in Moscow’s favor. The Senate failed to pass a procedural resolution challenging Trump’s war powers in Iran. Moreover, Congress has done little to advance the defense authorization bill: While the House barely passed its version of the Fiscal Year 2027 National Defense Authorization Act in July, Senate Democrats blocked their chamber’s version of the bill in protest over the war with Iran in the same month, and have not advanced the bill since. Not coincidentally, Republicans find themselves facing significant election losses, defending their record and a historically unpopular president and administration amidst an ongoing war and executive overreach.
Nowhere has executive expansion been more pronounced than at the Department of Defense, where the administration has asserted broad control over defense contractors, authorized legally dubious strikes on alleged drug smugglers, and conducted decapitation operations against foreign regimes. Recently, Secretary of Defense Pete Hegseth outlined even more significant expansions of department power and recently declared he will shrink the general/flag officer corps by 20 percent despite bipartisan concerns. Republican leaders have largely acceded to this consolidation of executive power, and their reasons for going along are straightforward. Members of Congress largely live in fear of their voter bases and face the most risk from the president opposing them in primary elections or suppressing the Republican vote in general elections, as demonstrated in the many high-profile primary losses by Republican incumbents this year following Trump endorsements of their opponents.
Yet while the record of the current Congress may seem like continued surrender to the administration’s strategic and fiscal goals for the military, the details of the current dynamic reveal a more complicated situation. Quietly, in the FY26 National Defense Authorization Act and in the evolving FY27 bill, Congress has established tools to reclaim its constitutional role in shaping U.S. defense strategy — relying on procedure, statutory mandates, and funding decisions rather than public confrontation to do so.
While Congress has so far failed to defend the very limits to executive power it authored, the coming months will set the scene for an oversight role amid a more complicated dynamic. With the midterm elections increasingly likely to give Democrats at least partial control of Congress, congressional oversight will be challenging. The administration has announced in response to recent statutes born of the FY26 National Defense Authorization Act that it does not believe Congress has the authority to limit its power or has outright refused to follow congressional direction. Congress cannot legally enforce its statutory requirements over a disobedient executive: It must use its constitutional powers to impose compliance through appropriations, oversight, and even impeachment.
Regardless of how difficult, a future Congress can and should use its powers to limit executive overreach and reassert its role in overseeing national defense.
Three Visions of American Power
Over the past year and a half, the Trump administration expanded executive power and concentrated decision-making at a scale with few modern precedents, most prominently within the Department of Defense. Operationally, it executed a series of large-scale military actions — including strikes in Venezuela, expansive maritime interdictions in the Caribbean, and a sustained offensive campaign against Iran — all conducted with little congressional oversight or authorization. At the same time, the administration pursued structural changes to Department of Defense leadership, removing senior civilian and uniformed leaders at an unprecedented pace while advancing plans to remove additional military leaders and merge U.S. Northern Command and Southern Command into a new Western Hemisphere Command. Major acquisition programs and contracts were also canceled or restructured, while defense contractors have been subjected to heightened Department of Defense control, which may be inconsistent with existing statutory and regulatory frameworks.
These shifts — and the tensions between the executive and legislative branches — were first and most clearly reflected in the documents that now define U.S. defense strategy: the 2025 National Security Strategy, the 2026 National Defense Strategy, and the recent National Defense Authorization Acts.
The 2025 National Security Strategy marked a decisive narrowing of U.S. global influence. Adding narrative structure to President Trump’s own strategic instincts, it rejected post-Cold War assumptions of global primacy in favor of regional balances of power and selective engagement in world affairs. In a break from what has historically been U.S. defense strategy to focus on threats posed by China, Russia, Iran, and North Korea, the National Security Strategy prioritized the Western Hemisphere, homeland defense, migration control, and economic security. China was framed as a competitor to be managed rather than a systemic adversary threatening democratic nations, and allies were similarly viewed as transactional partners: pay more for defense or face less U.S. commitment. Ironically, the administration’s war against Iran highlights its lack of consistency within any strategic framework.
The 2026 National Defense Strategy, directed by longtime China hawk Undersecretary of Defense for Policy Elbridge Colby, attempted to reconcile this worldview with operational realities. It continued to treat China as the pacing military challenge and emphasized deterrence by denial, forward posture, and coordination with allies. At the same time, it incorporated the administration’s Western Hemisphere-first priorities, producing a document that straddled competing imperatives, aligning rhetorically with the White House while preserving core elements of traditional U.S. defense posture.
In contrast, Congress articulated a far more historically consistent position of U.S. global leadership through funding and statutory direction. The FY26 National Defense Authorization Act and related appropriations sustained a U.S. role in international stability with a globally-postured, competition-centric military along with strong support for and commitment to Europe, Ukraine, and the Indo-Pacific.
The National Defense Authorization Act: Congress’ Oversight of Defense Strategy
The National Defense Authorization Act has historically served as Congress’ vehicle for providing direction in defense strategy: authorizing programs, setting toplines, and providing broad guidance on U.S. relations with allies and adversaries while leaving operational discretion to the executive branch. While the National Defense Authorization Act often reflects continuity and consensus rather than confrontation, Congress and the president have regularly diverged in the past on how each views national security risks, including disagreements over troop commitments, capabilities, and oversight. The Goldwater-Nichols Act of 1986 restructured the joint command system over Pentagon objections, the Nunn-Cohen Amendment to that bill established U.S. Special Operations Command despite resistance from the services, and post-9/11 Congresses used the bills to constrain executive discretion on detention, interrogation, and intelligence reporting.
The FY26 National Defense Authorization Act and the emerging FY27 bill expand on this construct. Rather than ratifying the administration’s narrower concept of American power and exercising broad authorizations, with the recent bills, Congress has diverged from the president’s view — as was previously noted in another War on the Rocks article specifically highlighting Congress’ attempts to check the administration on acquisition. Strategic directives in the National Defense Authorization Acts show Congress asserting its own judgment and intention to preserve U.S. global influence, reinforce commitments to allies and partners, and hold the Department of Defense accountable through prescriptive reporting and notification requirements on force deployment and leadership changes. In doing so, it challenges the assumption that defense strategy, force posture, and alliance management are solely executive prerogatives.
Preserving U.S. Global Influence & Continuing Commitments to Allies
The FY26 National Defense Authorization Act’s Senate preface proclaims the congressional view that the United States is operating in “the most dangerous threat environment since World War II,” driven by an “axis of aggressors” — China, Russia, Iran, and North Korea — whose shared resources and objectives threaten U.S. international influence and security. The FY27 National Defense Authorization Act drafts reflect a similar perspective. The Senate executive summary states that its singular goal in increasing defense funding is to deter the “axis of aggressors”, noting that these nations share “ambition and weapons” with an eye to weaken the United States and rupture alliances among democracies.
Congressional actions in the FY26 National Defense Authorization Act and the FY27 drafts related to the Indo-Pacific region and Europe demonstrate a global attention that diverges from the administration’s homeland and Western Hemisphere-focused defense strategies. Congress states its “sense” in the bills that the United States must strengthen its alliances to maintain strategic advantage over China. While similar language has appeared in prior bills, the FY26 National Defense Authorization Act is more insistent: mandating co-production, base integration, and industrial collaboration despite administration rhetoric downplaying China as a military threat and instead emphasizing transactional relationships.
Congress also legislated a more historically consistent approach with commitments to NATO. In the FY26 National Defense Authorization Act, Congress directs the Department of Defense and U.S. European Command to implement NATO’s strategy for deterring Russian aggression in the Baltics, specifying the capabilities to be deployed.
Further, despite the White House’s distancing from European allies, Congress reformed defense technology transfer programs and foreign military sales well beyond typical authorizing language, to allow for allies and partners to have greater access to U.S. technology. Section 1086 mandates a new department framework for defense-related technology transfers, specifying ten required elements to streamline approvals, consolidate governance, and incorporate structured input from other agencies and industry. Reforms to Foreign Military Sales impose clearer timelines, expand data sharing with allies and partners — particularly in AI, quantum, and autonomous systems — and require greater responsiveness to partner needs, including eligibility for non-program-of-record systems and commercial solutions. To enforce the mandates, Congress requires the Department of Defense to provide briefings, reports, notifications, and metrics on the programs.
Taken together, these provisions reflect Congress asserting its oversight role through statutory mandates, funding, and access to detailed information to institutionalize U.S. global influence and alliance integration towards a globally-oriented, tech-forward defense industrial base. In these sections, Congress did not enforce the administration view that partnerships are transactional: It reinforced the ladministration’s for collaboration, technology sharing, and joint development likely to respond to the advancing Chinese threat.
Demanding Transparency and Accountability
In the FY26 National Defense Authorization Act, Congress asserted control through the power of the purse, embedding strategic influence over combatant command structure by freezing funds for certain restructuring efforts unless the Secretary of Defense certifies to Congress that the decision serves U.S. national security interests. It also required that the department certify it consulted with allies and partners on the restructure and directed an analysis of the U.S. military’s ability to operate in the respective region — including impact on training and major exercises and to respond to threats from China and Russia. Congress further froze Army funds for restructuring its Joint Munitions Command and Sustainment Command unless the Secretary of the Army submits a report to the armed services committees comparing current and proposed structures and impacts on readiness.
The FY26 National Defense Authorization Act tightens Congress’s grip on U.S. military posture in Europe, freezing FY26 funds for any cut to troop levels below 76,000 unless the commander of European Command and the Secretary of Defense independently certify to Congress that such efforts serve U.S. national security. Significantly, in acknowledgement of relations with NATO, these sections also require consultation with NATO allies and relevant partners before executing these actions. Section 1268 of the FY26 National Defense Authorization Act carries similar mandates on funds if the department plans to draw down troops in South Korea below 28,500.
The House version of the FY27 National Defense Authorization Act reaches backward, demanding that the department provide its analytical basis for every European Command posture adjustment since Jan. 20, 2025, and that the Government Accountability Office provide an independent assessment of the department’s analysis. The Senate version of the FY27 bill provides even greater direction, outlining a new structure for unified combatant commands, including unified commands for Europe and North Africa, respectively.
Finally, Congress responded to the administration’s reshaping of Department of Defense leadership by creating new statutory mandates when leadership is removed or transferred, codifying its authority to scrutinize executive action and to create a public record of department decisions.
In a direct response to the February 2025 dismissals of Army, Navy, and Air Force Judge Advocate Generals, the 2026 National Defense Authorization Act requires the Secretary of Defense to notify the armed services committees and detail the reason for removing such leadership within five days of the action. The Secretary also must notify Congress if an officer is removed from a selection board report for any reason other than misconduct within thirty days of removal and before submission to the Senate’s promotion list.
Similarly, under the FY26 bill, if the President removes or transfers a member of the Joint Chiefs of Staff or combatant commander, he must notify Congress within five days and explain why the decision was made. The House FY27 draft further proposes amending U.S. Code Title 10 to require the Secretary of Defense to notify armed services committees within five days of removing a two-star or above general officer and include the concerns that resulted in removal.
What’s Different This Time
What distinguishes the FY26 National Defense Authorization Act and the emerging FY27 National Defense Authorization Act is not any single provision, but the cumulative use of statutory mandates, funding fences, and detailed reports from the department on its actions. This combination reflects a Congress that, while publicly deferential, is quietly reclaiming institutional ground: using the authorization process not merely to maintain defense programs, but to subtly constrain executive discretion and preserve a globally postured U.S. military aligned with its own priorities and its vision of U.S. national security.
Congress has further asserted structural control over the department, demanded visibility into leadership decisions, directed changes to foreign military acquisition and technology transfers, and defined its expectations in Europe and the Indo-Pacific. By requiring input from allies and partners, unfiltered assessments from commands, and written certification for restructures, Congress has demonstrated skepticism of the department and created genuine leverage. By building legal preconditions for the department to act, Congress has established itself as the gatekeeper for U.S. commitments to allies and partnerships and defended its influence over U.S. national security to include a global defense posture.
Will It Matter?
Whether Congress can assert any real independence and exert control over the administration depends on a simple question: whether it will seek to enforce the statutory requirements it authored in the National Defense Authorization Act through oversight, and ultimately, funding. So far, the answer has been a clear “no.”
One early test of Congress’ resolve arrived with the firings of several senior leaders, including Army Chief of Staff Gen. Randy George. Hegseth provided neither the five-day notice nor a written explanation as Section 911 of the FY26 National Defense Authorization Act — adopted in December 2025 — mandated. On removing names from selection board reports, Hegseth has been more aggressive: In March and August 2026, Army colonels were removed from the brigadier general promotion list, and in September 2026, six general officers were removed from the two-star promotion list. Congress’ response to these actions was telling in its absence: lukewarm questions to Hegseth during his testimony over the proposed Pentagon budget without demanding a formal explanation for the terminations. The very provision Congress wrote to assert its oversight role was ignored without consequence.
On force posture, the department announced it would remove approximately 5,000 U.S. troops from Germany without any explanation for its decision and redeploy the troops to Poland, while making plans to pull back troops made available to NATO. Hegseth also recently suggested that troops may be redeployed from NATO to the Western Hemisphere: consistent with the administration’s national security strategies, but inconsistent with congressional views on defense needs. While not yet overstepping the FY26 National Defense Authorization Act’s requirement to provide written justification for troop levels in Europe below 76,000, the moves signal that Congress may soon be confronted with another violation.
Furthermore, the Office of Management and Budget provided a Statement of Administration Policy opposing the National Defense Authorization Act provisions limiting the administration’s discretion over foreign policy, military leadership, and force posture decisions. The Office asserted that the statutes unduly constrain the Secretary of Defense’s ability to manage military leadership, interfere with the president’s constitutional authority as commander in chief, and could impact rapid military response to national security crises.
With these actions, the administration has signaled it intends to ignore congressional direction, either through stated constitutional objections or outright noncompliance. If Congress does not defend its mandates, it likely will not enforce the broader architecture of National Defense Authorization Act oversight, and the executive branch may continue grasping power without accountability.
As noted, the reasons for congressional leaders failing to confront the administration are clear: Congressional Republicans face the greatest electoral threats from their most strident voters, who have remained largely supportive of the president. There are, however, pockets of congressional courage.
Congress’ limited steps towards independence were in part revealed to us in the days leading up to passage of the FY26 Consolidated Appropriations Act in February. In the lead-up to the bill’s passage, Congress hotly debated Department of Homeland Security funding in the wake of high-profile shootings by Immigration and Customs Enforcement, leading to a four-day shutdown before the bill was finally agreed to. Beneath the public debate, though, we witnessed a process largely led by longtime appropriator Rep. Tom Cole (R‑Ok.) that was kept deliberately opaque until the final stages, with key details withheld not only from stakeholders but from the administration itself until outcomes were locked in. While appropriators have long been fiercely independent — even parochial — in funding decisions, this marked a departure from a recent period defined by negotiations at the whims of the executive. In practice, the process functioned as a quiet affirmation of institutional power: Congress using procedure, rather than public confrontation, to reassert authority over funding and strategic direction.
As Congress debates the FY27 budget, appropriators are again showing glimpses of independence. The administration’s unprecedented $1.5 trillion budget request for the Pentagon came in two stages: $1.15 trillion through normal appropriations, with the remaining $350 billion tagged for another round of budget reconciliation. Sen. Mitch McConnell noted that the use of the party-line budget tactic could threaten long-term, strategic reliability for defense funding. In the subsequent months, events have played out much as critics predicted: While the House approved $1.07 trillion in regular appropriations for the Defense Department — the Senate has yet to pass a bill, but will probably fund the department at similar levels — they only provided $73 billion in a reconciliation package, including for Iran War funding. The Senate delayed another reconciliation package entirely until after the election, with even Republicans opposing it.
On the Iran War, there have been similarly limited signs of Republican pushback. The House voted three times to direct the administration to remove forces from hostilities with Iran. In June, such a resolution passed the Senate as well. The administration quickly rebuffed the action, claiming the resolution lacked the force of law and that hostilities had ceased after the short-lived April ceasefire. A subsequent resolution failed when Sen. Bill Cassidy reversed his vote following direct lobbying from the White House and assurances that the conflict would soon end — demonstrating the president’s continued influence within his party.
The most recent effort to end the war failed by just two votes in the Senate in September, this time with seven House Republicans and four Senate Republicans joining the resolution and Sen. John Fetterman (D-Pa.) voting against. Though such a resolution is unlikely to force the administration to withdraw from the region, the growing opposition may reflect momentum to limit the conflict given intense public disapproval. On the campaign trail, several vulnerable Republican candidates have made appeals to end the war, if only to lower gas prices for consumers. While milquetoast at best, these statements —combined with growing frustration with Hegseth’s leadership among Senate Republicans — may signal renewed interest in limiting executive power following a strong electoral mandate in November.
Given current projections, Democrats are likely to take the House in the November elections, and increasingly likely to take the Senate as well. A Democratic Congress in January has been given the tools necessary to apply real oversight over the Department of Defense and the future of national security strategy. In any case, Congress should step up to its coequal role in providing for and overseeing the conduct of national defense, regardless of party control.
What Congress Should Do
Congress should use all the powers at its disposal to achieve oversight of the department and to limit the executive branch, to achieve both an effective, long-term defense strategy and a healthy balance of power in the federal government. A new Congress in January, whether under unified Democratic or divided control, will have the opportunity to do so using the tools it embedded in recent National Defense Authorization Acts to assert its role in defense strategy.
First, Congress can freeze funds. For example, in the FY21 National Defense Authorization Act, it blocked funds for troop drawdowns in Afghanistan and mandated troop levels in Germany in a similar construct to the FY26 and FY27 bills. When President Trump vetoed the bill, Congress enacted it over the veto. If the department goes on to use funds against authority, those doing so would likely violate the Anti-Deficiency Act, which — although it has never been prosecuted — criminalizes (, among other things, obligating or expending funds without appropriation to do so. However, without a Department of Justice or Inspector General Office willing to investigate, prosecute, or report violations to Congress, repercussions are unlikely.
Congress can also delay confirmations and compel testimony and information using subpoenas if the department fails to provide statutorily mandated notifications, reports, or certifications. However, if the administration continues to ignore or object to congressional directives, Congress’ options for enforcement are limited. Courts will likely not support lawsuits by Congress against the administration to enforce statutory language, as they usually determine that members lack standing to bring the action or that the dispute is not a legal issue but rather a “political question.”
Even less probable is the use of War Powers. While a Democratic majority in 2027 would certainly revisit the question if the conflict in Iran continues, the administration has already demonstrated it would likely ignore such action. A dispute of this kind would almost certainly end up in the Supreme Court given claims by successive administrations since President Richard Nixon that the 1973 War Powers Resolution is at least partially unconstitutional.
Congress instead needs to use its constitutional oversight powers: appropriations, confirmations, investigations, and even impeachment. Congress can and should restrict funding if the administration does not comply with the statutes it has written. Members should deny confirmation to nominees that do not reflect appropriate deference to Congress’ role. Democratic-controlled chambers will undoubtedly conduct investigations into the department’s conduct over the past several years, even if Republicans maintain control of the Senate. Finally, Congress should consider impeaching officials who disobey congressional directives, as they already tried with Hegseth, including even the president.
The recent National Defense Authorization Acts have clearly expressed congressional intent, seemingly designed to restore control over defense strategy, force structure, and executive accountability. But they do not supply political will. Whether Congress treats the National Defense Authorization Act and related appropriations as tools to control the executive branch and to influence U.S. defense strategy, or whether it allows its powers to fade into the background, will be revealed in the coming months. Either way, the next Congress needs to take action to assert its oversight of the executive branch and its vision of U.S. national security, because it will determine the future of U.S. national security well beyond this administration.
Margaret M. Cassidy is an attorney advising U.S. and non-U.S. companies on federal acquisition, export controls, and intellectual property. She works with founders, boards, and executives to integrate regulatory risk management into growth strategy, global expansion plans, and government partnerships. With experience spanning startups to global enterprises, including senior roles at General Electric Transportation and PwC, Margaret has also served as a government-approved independent monitor for contractors facing debarment and is on the National Defense Industry Association’s Women in Defense National Advisory Board.
Andrew Swick is a strategic consultant and lobbyist who has spent years counseling small, medium, and Fortune 100 companies and organizations. Andrew is a graduate of Georgetown University and the U.S. Military Academy at West Point. Following his Army service, he worked as a policy researcher in national security with the Center for New American Security and the National Commission on Military, National, and Public Service before transitioning to government affairs.
Together, we co-edit The Defense Salon, a newsletter and blog focused on acquisition, national security, and defense policy, where we provide a deep-dive analysis of the FY26 National Defense Authorization Act.
**Please note, as a matter of house style, War on the Rocks will not use a different name for the U.S. Department of Defense until and unless the name is changed by statute by the U.S. Congress.
Image: SECWAR via Wikimedia Commons
