As the 2020 campaign gets underway, we’ve heard about a Green New Deal, Medicare for all, breaking up Amazon and universal basic income — to name but a few of the ideas raised by Democratic presidential hopefuls. But one issue has been largely absent: foreign policy — the potential use of force, great-power competition and the management of alliances that will be more important during the next presidency than it has been in three decades.

Maybe I missed it, but I haven’t heard any of the Democrats running on the argument that he or she is the best person to answer the White House crisis line at 3 in the morning. They all seem inclined to let that call go to voice mail. I hope that doesn’t last, because that phone will be ringing. This will be an extraordinarily volatile and confusing time for U.S. foreign policy.

We’re in the post-post-Cold War era — an era when being secretary of state, let alone president, has become a terrible job. (If anyone asks you to become secretary of state, say you had your heart set on secretary of agriculture.) The post-Cold War era had its issues — 9/11, Iraq and Afghanistan, to be sure — but it was in many ways a unipolar belle epoque, in which an American hegemon stifled any serious great-power conflict.

The post-post-Cold War era, which has been slowly unfolding since the early 2000s, requires a president to manage and juggle three huge geopolitical trends — and the interactions between them — all at once.