Pity the president.

• Author: Krebs, Ronald R.
• Position: Essay

Donald Trump is so singular a figure in background and temperament, so large a personality, and so seemingly immune to the usual pressures and incentives, that it is tempting to imagine that foreign policy under him will be simply the projection of his will. Think again. Like presidents before him, Trump will learn that going solo is not a recipe for an effective and enduring foreign policy. Always fraught and frustrating, the domestic politics of foreign policy have in recent years become even harder for presidents to manage. Trump will be no exception.

Trump the presidential candidate seemed to care little about building a coalition. Deriding the corrupt politics of Washington, he rode a populist wave to the White House. Trump the president needs those very elites whom he had previously spurned. Trump the presidential candidate reveled in the politics of division: American politics had become highly polarized across party lines well before he became a contender for the Oval Office, but Trump carved and mined new seams. Trump the president cannot govern through division alone.

Even a president with greater discipline and thicker skin than Donald Trump, however, would find foreign-policy leadership daunting. Two central tasks--setting the agenda, and building and maintaining a supportive coalition--have become much more difficult as audiences have become increasingly fragmented and diverse and as politicians have refrained from horse trading for fear of WikiLeaks-style exposure. Even if Trump were suddenly to embrace the politics of unity, he would discover that a durable coalition is an unattainable dream.

Presidents have every incentive today to retreat from sweeping narratives, provide very targeted "side payments," and craft narrow coalitions to support their policy initiatives. Barack Obama's modest ambitions in foreign affairs, his instrumental rhetoric and his pragmatic inclinations reflected his domestic circumstances as much as they did either the world or his personality. And these same circumstances will confront President Trump.

Presidents have a much freer hand in foreign than domestic policy. The president is commander in chief of the military and can call upon the State Department, the intelligence community and the larger federal bureaucracy. Not only are Congress's formal powers in foreign affairs limited--considering treaties for ratification, issuing declarations of war, controlling the purse and holding hearings--but it has eagerly shed what few responsibilities it has. With good reason, presidents look to the international arena to make their mark, especially when their domestic programs are stymied and when they are lame ducks.

But presidents cannot long go it alone in foreign policy. They require funds, and so any major initiative eventually needs congressional authorization. They require at least the acquiescence of the public, as numerous, vocal domestic critics will scare off international partners. Sometimes, they require the public's more active endorsement, to bolster their leverage with and clarify their intentions to foreign interlocutors. Few presidents concentrated foreign policy in the White House as much as Richard Nixon. But even Nixon knew that detente could not survive without a reservoir of public support. He and Henry Kissinger thus (over)sold detente as heralding a fundamentally changed international order. However, they never really thought of detente as an end to the Cold War, but rather as its continuation in a less confrontational guise. When it became clear that Cold War rivalry had not been extinguished but had merely gone underground, public support withered and detente collapsed.

Presidents used to have an easier time exercising leadership in foreign affairs. This was partly due to the president's institutional advantages: as holder of the only nationally elected office, somewhat above sordid partisan politics; as commander in chief of the armed forces, in possession of classified information; and as head of the executive branch, with the power to implement and not just pronounce. These, in principle, bequeathed to presidents unparalleled legitimacy and endowed them with special authority, especially on national security. As Woodrow Wilson long ago observed, "There is but one national voice in the country, and that is the voice of the President."

But the presidency also came to occupy a unique and preeminent place in American political culture. Americans do not look to the president to tell them what to think about specific policy proposals. But they still look to the president to make sense of developments at home and abroad, to render meaningful a world that sometimes seems disconcertingly chaotic and meaningless. As Obama observed at the end of his first term, in a moment of reflective self-criticism, the presidency is not just about "getting the policy right," but equally about "tell[ing] a story to the American people that gives them a sense of unity and purpose and optimism, especially during tough times." The nation's narrator in chief resides in the Oval Office.

Leadership has never been easy: the bully pulpit has not allowed presidents to bend mass opinion smoothly to their will even on security matters, and persistent opposition frustrated the agendas of even committed, oratorically talented presidents like Franklin D...