“Help is on its way,” U.S. President Donald Trump promised in January, as Iranians took to the streets and were killed by the thousands by government forces. Six weeks later, the U.S. military offensive against Iran began. Trump offered several rationales, including the claim that the American attack would provide Iranians an opportunity to bring down their regime and replace it with something better. “The hour of your freedom is at hand,” he said to Iranians in a video address the night the war began. “When we are finished, take over your government.”
Trump’s implicit assertion was that the Iranian people wanted U.S. military intervention. Although some prominent Iranians in exile—such as Reza Pahlavi, the son of the deposed shah—supported this claim, the opinions of the wider Iranian public remained unknown. Even though many Iranians clearly opposed the regime, it does not follow that they welcomed U.S. and Israeli bombs.
Trump is not the only American president to have claimed that the U.S. military had invaded a country to help the people there and to infer that the invasion therefore had local consent. Military campaigns over the past several decades have always been given a strategic rationale—the defense of the United States, the defense of an ally, or, in the case of Iran, the destruction of Tehran’s nuclear program. But U.S. leaders have also frequently cast intervention as something the local population wants, as Vice President Dick Cheney famously did in 2003, when he predicted that U.S. troops would be greeted as liberators in Iraq. Trump has similarly mused that the people of Canada and Greenland would welcome being incorporated into the United States, and his administration invoked the suffering of Venezuelans under President Nicolás Maduro to suggest that the public approved of Maduro’s forcible removal in January.
It should not be surprising that American leaders make these claims. Consent implies a powerful moral justification for intervention, and research I conducted with the scholars Emily Myers and Livia Schubiger found that Americans are more inclined to support military intervention when the local population consents. Yet U.S. leaders are often guilty of claiming local consent when they have no evidence of it. Making the case that the local population will benefit from U.S. intervention—which can evoke the paternalistic rhetoric used to rationalize Western imperialism and colonial subjugation—is not the same as demonstrating that the local population actually approves of the mission.
If Americans are more likely to support a military operation that has local consent, then it stands to reason that an operation justified on these grounds will lose support if it becomes apparent that the local population does not, in fact, welcome U.S. meddling. Doubts about the Iranian public’s support for U.S. intervention—doubts that grew after Iranians did not heed Trump’s call to rise up against the government amid an air campaign that caused thousands of casualties in Iran, wrecked its economy, and likely tightened the regime’s grip on power—may now be contributing to the war’s unpopularity among Americans. And as Washington contemplates another military intervention, this time in Cuba, it ought to try to find out what Cubans really think first—not just as a matter of principle but because misrepresenting the preferences of a population abroad can have political consequences at home.
A PRINCIPLED STANCE
In March 2023, we conducted a large-scale survey experiment with 3,360 adult U.S. citizens that was designed to test how local consent affects public support for U.S. military intervention. Respondents evaluated hypothetical scenarios involving a U.S. air campaign to stop the persecution and killing of an ethnic minority group in a fictional country. The scenarios included four variables: the level of support for the intervention among the ethnic minority group, how many members of the minority group would be injured or killed by U.S. strikes, how many bystanders from the ethnic majority would be injured or killed by U.S. strikes, and how likely the intervention was to succeed.
Local consent substantially increased respondents’ support for military intervention. When almost all members of the ethnic minority group supported the operation, respondents were 19 percentage points more likely to favor it than they were in scenarios in which the military action had almost no local backing. That increase was roughly the same as the difference in respondents’ favorability toward the mission when the odds of success were 95 percent compared with 50 percent. Expectations of civilian casualties had an effect on a similar scale. Respondents’ support for military action was 24 percentage points higher in scenarios that were projected to have zero civilian casualties among the ethnic minority group than in scenarios with 2,000 expected casualties, and there was a 22-point difference in support between scenarios with zero and 2,000 bystander casualties.
Local views matter to Americans.
The findings indicate not just that consent matters but also why it matters. One potential explanation would be that local support is a signal: if the people being rescued want the intervention, it is probably more likely to succeed. If they do not, U.S. troops might encounter more effective resistance, and Washington’s political aims might be harder to achieve. Yet our experimental design allowed us to rule out the possibility that this signaling function is the only way in which consent matters. We told respondents the projected costs and likelihood of success upfront, and these variables were not dependent on the estimates of local support in the different intervention scenarios. Respondents still cared about consent.
That suggests a more likely explanation: principle. Even in scenarios projected to be essentially costless in terms of civilian casualties, respondents were more likely to support intervention when it had the blessing of the local public. They apparently viewed consent not merely as a practical concern but as a matter of moral principle.
It is more difficult to pinpoint how local consent shapes the American public’s support for real-world military campaigns, because many factors affect public support for war, and most polls do not ask Americans if they believe that the local population welcomes U.S. intervention. The plausibility of U.S. policymakers’ claims of local consent, moreover, likely varies in the eyes of the public. Yet there is some evidence corroborating the idea that local views matter to Americans. In March 1999, when NATO initiated a bombing campaign in Serbia on behalf of Kosovo Albanians who were facing ethnic cleansing and displacement, local public discourse was strongly favorable toward the United States and NATO. The day before the intervention, the front page of Koha Ditore, an influential Albanian-language newspaper in Kosovo, ran a headline that read, “NATO, Just Do It.” At the start of the campaign, a poll showed that 60 percent of Americans approved of it, and 70 percent identified protecting civilians as a very important reason for the intervention.
There is also some reason to think that Americans accepted their government’s claims of local consent for the 2003 U.S. invasion of Iraq. Before the invasion, there was no reliable polling inside Iraq that could tell Americans directly what Iraqis thought about the prospect—although the single-digit support for the invasion in neighboring Arab states might have provided a clue. Still, the Bush administration confidently asserted that Iraqis would welcome liberation. Polls conducted in the United States in the spring of 2003 found that majorities of Americans believed the administration’s claims that Iraq possessed weapons of mass destruction and that the country had links to al-Qaeda. If they believed policymakers on those counts, Americans might also have believed that U.S. soldiers would be greeted as liberators. These same polls showed that public support for the invasion exceeded 70 percent.
WHAT IS CONSENT?
U.S. administrations that make unfounded claims of local consent for intervention risk losing political support when those claims prove false, just as they would lose support if they misled the public about a military mission’s projected costs or likelihood of success. The onus is on policymakers to establish what the local population prefers before making the decision to intervene.
In some cases, local preferences are clear. Canada and Greenland are both peaceful democracies with readily available and reliable opinion data. In early 2025, polls found that between 75 percent and 90 percent of Canadians and around 85 percent of Greenlanders opposed annexation by the United States. Their objections to U.S. intervention have been loud enough to reach the ears of many Americans, diminishing Trump’s power to claim local consent. These prospective land grabs are correspondingly unpopular in the United States; in early 2025, YouGov found that only 36 percent of Americans supported the annexation of Canada and only 33 percent supported the annexation of Greenland. Another poll from the same time showed that 77 percent of Americans agreed that Canada should join the United States only if Canadians chose to do so. Just five percent supported the use of economic coercion, and one percent supported the use of force to annex Canada.
More often, it is difficult to make local preferences known before a military intervention. In war-torn places, large representative surveys are practically impossible. In authoritarian countries, people who fear persecution have good reason to hide their preferences or avoid answering questions. Opinion gathering inside Iran is complicated for both reasons. Many Iranians apparently oppose the regime and are willing to take great risks to defy it, as the deadly protests earlier this year made clear. But that does not amount to evidence that Iranians want violent regime change brought about by the United States and Israel. Diaspora opinion might be easier to solicit, but it cannot be treated as representative of the opinions of those who directly bear the burdens of U.S. intervention. Diasporas themselves may also be divided: one poll among Iranian Americans found that attitudes toward the U.S.-Israeli intervention were evenly split between support and opposition in the first week of the conflict.
In rare cases, when crimes against humanity or genocide are unfolding and military intervention could conceivably stop these atrocities without making things worse for the local population, it may be justified to assume local consent rather than let the window for action close. If Trump had intervened in Iran at a time and in a manner that would have protected Iranian demonstrators from government brutality, his administration would have had a stronger moral case for intervention, and public support in the United States might have been higher as a result. But that is not what Trump did, and most situations are not sufficiently urgent to justify bypassing a good-faith attempt to find out what local populations prefer the United States to do. That effort might include communicating with credible civil society organizations that have meaningful relationships with affected communities or consulting with UN agencies that maintain a presence in the country and might be able to provide similar insight. Policymakers would then need to make judgments about what evidence is sufficient and what counts as sufficient consent, whether it is a majority of the local population or some other threshold.
If it proves impossible to establish what local people want, U.S. leaders should not try to claim consent anyway. They would be ignoring the will of the local population, lying to their own people, and jeopardizing any support for war they have at home. American citizens are not indifferent to the desires of populations in countries their president proposes to liberate. For U.S. policymakers to ignore local opinion and American preferences is not just morally wrong. It is also bad politics.
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