Red or Blue? How party ID codes our positions on foreign policy

Americans are divided neatly along party lines on their opinion of U.S. military action against Iran, according to surveys conducted since the Iran war began on Feb. 28.

But this is far from the only foreign policy issue dividing Americans by their party ID. In fact, according to the Chicago Council on Global Affairs, this is reflective of a problematic trend: the partisan divide on U.S. foreign policy public opinion has been widening for decades and is only growing.

The Chicago Council on Global Affairs first began polling Americans on their foreign policy opinions in 1974. Nearly five decades of surveys later, Managing Director of Public Opinion and Foreign Policy at the Chicago Council Dina Smeltz said the most notable development is that the polarization that has long affected domestic policy is now extending to foreign policy.

“A lot of it is relevant today, and these divisions are growing wider,” Smeltz told Responsible Statecraft. “In our data, more than anything else, partisanship really seems to determine how people view foreign policy strategies, whether they support or oppose a particular initiative.”

Even as recently as the early 1990s, Smeltz said, Americans had a lot much more overlap on what they considered most important when it came to U.S. Foreign Policy. Some of these agreements have held strong today: most Americans still think the U.S should play an active part in world affairs, still support alliances and international trade, and can still agree on when the U.S. should use force, Smeltz told RS.

The differences come when Americans are asked how to “put those principles into action and how to address the primary issues facing the United States and the world in terms of security challenges,” Smeltz said.

For example, partisan opinions on the Russia-Ukraine war have widened considerably throughout the course of the conflict. By March 2025, Council surveys showed a 47-percent point difference between Democratic and Republican support for the U.S. providing military support to Ukraine, with 77% of Democrats in support and 30% of Republicans in support.

This is down considerably from the 50% Republican support in 2023 (Democratic support was about the same then). At the time, Republicans on Capitol Hill like Sen. JD Vance were vocally opposing further aid to Ukraine without a clear strategy to end the war. This was also a campaign issue for Donald Trump in 2024.

Furthermore, amid the Israel-Gaza conflict, Republicans and Democrats consider the country of Israel very differently too: on a scale, with 100 being favorable and zero being unfavorable, Republicans rated their feelings toward Israel as a 59 and Democrats rated their feelings as a 36.

Meanwhile, 63% of Democrats favor Palestinian statehood, while only 35% of Republicans do. Supporting Israel has clearly become more of a Republican-right issue over the last 20 years, while Democrats have been slowly peeling off, particularly as Israel’s ruling government under Benjamin Netanyahu has become more hardline and right wing over that time.

According to Smeltz, Americans with a wide variety of policy ideologies once viewed immigration, globalization, and engagement with China similarly. In early Chicago Council surveys, Republicans and Democrats tended to also agree on the prioritization of an overlapping set of foreign policy goals for the nation: protecting the jobs of American workers, maintaining the value of the dollar, securing adequate supplies of energy, pursuing worldwide arms control, and containing the spread of communism.

But this is no longer the case. Now, Republicans and Democrats see the world — and America’s role in the world — very differently. They still agree on the importance of protecting the jobs of American workers and preventing the spread of nuclear weapons. Beyond that, however, Republicans tend to prioritize maintaining superior military power worldwide and limiting global Chinese influence. Democrats prioritize limiting climate change and developing sources of renewable energy.

Furthermore, when the Chicago Council first surveyed about threats facing the U.S. in 1998, survey respondents of all partisan identities largely agreed on the same six threats. A decade later, in 2008, survey respondents still mostly agreed across party lines. In the most recent 2025 survey, respondents overlapped on only two items: international terrorism and government corruption.

Republicans ranked mass immigration and refugees into the U.S., the development of China as a world power, and Iran’s nuclear program among these threats, while Democrats ranked a weakening of democracy in the nation, climate change, and a global economic downturn.

Experts point to several different factors motivating the increasing partisan separation on foreign policy opinions. One is that as politics have become highly polarized between Red and Blue, the issues at the core of Americans’ political identity have become more nationalized. Everything from COVID vaccines, policing, and now foreign wars have become code for Democrat or Republican, as evidenced in polling on Gaza, Ukraine, and now Iran.

Party sorting — in which voters align all of their ideological beliefs with their corresponding political party — has taken place over the last few decades, contributing to “growing partisan divisions on almost every issue,” according to Morris Fiorina, professor of Political Science at Stanford University and a senior fellow at the Hoover Institution. “It’s not the voters who are changing so much, it’s the parties,” Fiorina told RS.

Divisive political rhetoric and discourse has also contributed to the growing gap, Smeltz said, and with a widening partisan divide, it becomes more difficult to “craft a foreign policy that will be palatable to the majority of Americans,” Smeltz said.

“It would be best to have a foreign policy and a government that is trying to address the needs and concerns of Americans, regardless of political affiliations, but the way things have been going in the past 15 years, it gets harder and harder to see the political will to cater to all Americans, not just those who represent your base,” Smeltz told RS. “I see both domestic challenges if this trend continues, as well as international ones.”

William Mayer, a professor of Political Science at Northeastern University, told RS that he is certain about one thing: with little evidence that Republicans and Democrats won’t continue to disagree about foreign policy, he doesn’t “see the partisan gap closing in any significant way soon.”