Foreign policy was once a domain that stood above partisan politics. But in today’s hyper-polarised political environment, many Americans weigh the value of US action abroad based on the president’s party affiliation. This occurs even as people across the party divide agree broadly on the nation’s priorities on the international stage. This is the opposite of the Truman-era notion that “politics stops at the water’s edge” and represents a risk in Washington’s ability to conduct a stable foreign policy. Surveying 1,248 American adults last August, the Korea Economic Institute of America discovered that people’s self-identification with a political party shaped their perception of foreign threats. Among Republicans, 61 per cent believed China posed the greatest challenge to US interests abroad vs 38 per cent of Democrats. Meanwhile, only 5 per cent of self-described Republicans agreed with 24 per cent of Democrats who saw Russia as the most significant threat to the United States. Interestingly, respondents from both parties broadly agreed when asked about specific issues in foreign policy. For instance, most Republicans (65 per cent) and Democrats (59 per cent) supported either increasing or maintaining US troop levels in South Korea . Only 17 per cent of Republicans and 18 per cent of Democrats called for either reducing or withdrawing troops. Similarly, 68 per cent of Republicans and 62 per cent of Democrats supported US help for South Korea in the event of a cyberattack from North Korea or China. A stark partisan divide only appeared when respondents were directly asked about President Donald Trump’s performance on the international stage. Among Republicans, 66 per cent approved of Trump’s handling of relations with North Korea , compared to only 9 per cent of Democrats. A smaller but similar divide between Republicans (63 per cent) and Democrats (24 per cent) appeared when respondents addressed questions about the Trump administration’s handling of US-South Korea relations . The partisan branding of foreign policy creates two problems for the country’s ability to advance peace. First, it makes it difficult to ratify and implement agreements. The Clinton administration’s efforts to denuclearise North Korea through the Agreed Framework in 1994 failed because of Pyongyang’s cheating. However, Republican political opposition in Congress also made it difficult to carry out the US side of the provisions and raised questions about whether the American government was committed to the agreement. Similar challenges may await future diplomatic agreements if the partisan dispute at home becomes so intense that Republican lawmakers are unable to support a Democratic administration’s foreign policy, and vice versa. The second problem with partisanship is that if there are Republican foreign policies and Democratic foreign policies, even if they differ more in name than in substance, foreign governments are inevitably going to wonder what will happen to their agreements with the US if there is a change in administration. At a minimum, they may insist on Congressional ratification rather than an executive agreement to try to make the deal more durable. However, with the political divide in Congress, this is unlikely. US must regain world’s trust after destructive Trump years Worse, they may be prepared to wait a year or two for an agreement if they think a more malleable US administration might come to power. At the extreme, they might calculate that they are better off with no agreement rather than an unreliable one, even if that might increase tension or create risks. The US repudiation of the Paris climate accord and the nuclear deal with Iran have raised questions about the point of negotiating with Americans. Foreign commentators have observed that, in both cases, US domestic politics seemed to be the source of US unreliability. What does this mean for ongoing threats such as the one posed by North Korea? From Pyongyang’s perspective, the partisan divide in the US reduces the pressure to negotiate. Kim Jong-un would have reason to doubt whether any US promise or reprimand intended to encourage the elimination of his weapons of mass destruction would be carried through. And it would not be just North Korea that would doubt our commitments. Regional partners essential to engagement with Pyongyang such as South Korea, China and Japan would also wonder about coordinating with Washington in case they are wrong-footed amid the partisan shift in US foreign policy every four years. America’s current hyper-partisanship may make it quixotic to hope for a bipartisan foreign policy, even though it would promote our national interest. Maybe the best we can hope for is to choose a few key areas in which both Democratic and Republican parties might engage in their own quiet diplomacy to settle on a common approach before advancing. It would be a start. Mark Tokola is vice-president of the Korea Economic Institute of America in Washington, DC. He retired as a US senior foreign service officer in 2014. Juni Kim is the senior manager for operations and technology at the Korea Economic Institute of America