Thanks to Trump, current and former officials say, Palestinians may never get a state of their own, Iran may shun diplomacy with Washington for the foreseeable future and U.S. allies may forever be reluctant to trust their American counterparts. Relations with China, the effects of climate change and ending nuclear proliferation are among other challenges a future president may find harder to tackle in a post-Trump world.

It doesn’t help that U.S. foreign policy is increasingly falling prey to partisan fighting in Washington. A Democratic president focused on reversing Trump’s legacy — the same way Trump has tried to erase Barack Obama’s legacy — runs the risk of feeding the perception that U.S. foreign policy will not remain stable over time.

“There is a hunger for the U.S. to get back to its traditional role on the world stage,” said Jeff Prescott, a former senior National Security Council official in the Obama administration. “But after Trump, many of our international partners are going to step back and ask whether signing up with us is going to be a long-term proposition.”