President Trump. (Joshua Roberts/Reuters)

President Trump has already made news, and stoked controversy, by advocating unorthodox policies in unusual ways. In particular, he has signaled a foreign policy that breaks from decades of tradition — questioning alliances including NATO, arguing with allies such as Australia, and advocating an expansion of U.S. nuclear arms, among other things. Ultimately, many longtime foreign policy experts fear that he could undo an entire post-Cold War order and destabilize the international system.

To do so, however, Trump may need the support not only of other political leaders but of the American public itself. Our research suggests that his ability to shape public opinion may be quite constrained. We find that Trump may be successful in mobilizing support among Republicans and some independents — but only for typical Republican policies.  For policies that would change the 50 years of U.S. grand strategy, he will likely have difficulty changing public attitudes.

How we did our research

In the weeks leading up to the November election, we conducted an experiment involving more than 1,500 American adults whom we contacted through Qualtrics, a prominent market research firm. Our sample included an equal number of Democrats, Republicans and independents, as well as an equal number of men and women.

In the experiment, participants were randomly assigned  to read different news stories about Republican candidates making statements about U.S. nuclear weapons policy, which has been a stable foundation of U.S. grand strategy.

Participants read news stories on one of three topics: criticizing the Obama administration’s nuclear deal with Iran; supporting the development of nuclear weapons by Japan, South Korea and Saudi Arabia; and using nuclear weapons to destroy ISIS. The Iran deal story represents a typical Republican foreign policy position, while the other two stories advocate major changes to U.S. grand strategy. All three were positions that Trump took during the campaign.

Half of the stories attributed the statements to Donald Trump, and the other half attributed the statements to Paul Evans, a fictional Republican candidate for U.S. Senate. We then asked participants their attitudes toward the Iran deal, the nuclear nonproliferation treaty (NPT), and the principle of “no first use” of nuclear weapons.

Attributing statements to Trump did not affect public attitudes any more than attributing them to the fictional Republican. Opposition to the NPT was essentially identical regardless of whether participants read about Trump or Evans supporting nuclear proliferation. Public opposition to the Iran deal was actually 5 percent higher when we attributed Trump’s rhetoric to Evans.  And public support for the first use of nuclear weapons was 6 percent higher when we attributed Trump’s  rhetoric to Evans.  But these differences were small and likely due to chance variation.

So, if voters respond to Trump like a “generic” Republican, what does that mean for his ability to shape public support for a new foreign policy strategy? Our results suggest that Trump could rally Republicans and some independents to support typical Republican policy positions, like opposition to the Iran deal.


Republican opposition increased from 62 percent to 79 percent once they read Trump’s critique. Among independents, opposition to the deal increased from 47 percent to 56 percent. There was no change among Democrats, unsurprisingly.

But participants were not persuaded by Trump’s statements that are outside the typical boundaries of U.S. foreign policy. The next graph depicts the impact of the nuclear proliferation story on attitudes toward the nuclear nonproliferation treaty (NPT) and the goal of eliminating nuclear weapons.


Reading the Trump statement advocating the spread of nuclear weapons has no impact on opposition to the NPT, regardless of whether it is attributed to Trump or Evans and regardless of the party affiliation of the reader. Indeed, reading Trump’s statement actually lowers Republican opposition to the treaty slightly.

Ultimately, a large and bipartisan majority supports this non-proliferation treaty, and reading Trump’s statement did not change that.

This same pattern holds regarding the use of nuclear weapons against ISIS.  Once again, Trump’s rhetoric did nothing to undermine popular support for the “no first use” policy regardless of whether the rhetoric was attributed to Trump or Evans, and regardless of the party affiliation of the reader.


Republican support for the first use of nuclear weapons is higher than among Democrats or independents, but it remains a minority position. Moreover, Republicans who oppose first use are unpersuaded by Trump’s rhetoric. This was also true if  we asked participants about using nuclear weapons against ISIS specifically.

Trump seeks a dramatic change in U.S. grand strategy, but sustaining policies that are unpopular will likely prove difficult over the long haul. Our experiment suggests that Trump will have difficulty persuading the American public to support many of his desired changes. Nuclear proliferation and the first use of nuclear weapons are not popular with Americans, and Trump’s rhetoric appears — at least thus far — not to change anyone’s minds.

Christopher Gelpi is chair of peace studies and conflict resolution at the Mershon Center for International Security Studies and professor of political science at  Ohio State University. He is the co-author (with Peter Feaver and Jason Reifler) of “Paying the Human Costs of War: American Public Opinion and Casualties in Military Conflicts.”

Elias Assaf is a PhD candidate in political science at Ohio State University.