America’s wartime presidents have often been elected on promises to avert or to end wars. In 1915, Woodrow Wilson declared, “There is such a thing as a man being too proud to fight.” Lyndon Johnson offered “peace without conquest.” George W. Bush pledged to avoid “nation-building” in his one serious statement about foreign policy during the 2000 election. Nonetheless, each of these presidents found himself embroiled in a war that cost thousands of American lives. And each left office deeply unpopular.

Donald Trump is not like any other president in American history, but he will probably fit this pattern. He has claimed, falsely, that he opposed the disastrous war in Iraq, begun by George W. Bush in 2003. He has condemned Barack Obama and Hillary Clinton for using military force to support the overthrow of Libyan tyrant Moammar Gadhafi. He has even hinted that he would work with Syrian dictator Bashar al-Assad and Russian leader Vladimir Putin, ending all American military support for rebel groups in Syria. Trump would clearly prefer to outsource the fight against ISIS and other extremists to regional dictators, minimizing human and financial costs for the United States.

This is the enduring, and deeply mistaken, allure of a widely held American idea about deterrence. Call it belligerent deterrence: If only we build intimidating military capabilities (“second to none”) and maintain a steady stream of threatening rhetoric about bombing our enemies into oblivion (and waterboarding them if we capture them), we expect challengers to cower in their caves. Thanks in part to the twisted logic promoted by Henry Kissinger and other “realists,” we expect that flexing our muscles will increase our “credibility” so that allies will fight on our behalf, and adversaries will back down and give us what we want, with “no concessions” on our part. To hear Trump and mainstream Republicans talk about contemporary Iran, they seem to expect the mullahs to turn over their nuclear capabilities to us, even without negotiations, because we are so strong, so tough, so righteous.

The political logic of belligerent deterrence sells well to American voters who want absolute security at little cost (our allies will pay for it, Trump promises), but the historical record is clear: Tough-guy posturing encourages challenges to American power, especially from adversaries who recognize how presidential claims exceed military capabilities and public support at home for follow-through. Allies have an interest in holding presidents to their rhetoric, using American pledges of strength to justify their own cuts in military spending. When adversaries challenge our toughness and allies call upon it—as inevitably happens—American leaders are stuck taking military action they never intended or prepared for.

Contrary to our bullying expectations, belligerent deterrence traps the United States in unintended wars. During the Cold War, that precise dynamic embroiled the United States in extended, bloody, unsuccessful wars in Korea, Vietnam, Angola, Lebanon, and Afghanistan. After the Cold War, the same logic turned the United States into an occupying power in the Middle East.

Trump’s presidency will bring us more of the same, with even worse consequences. He is not interested in policy detail, expertise, or experience. He bases his personal power on the very kinds of blustering rhetoric and muscular posturing that have caused so many problems for American policy in the past. Although Trump’s positions on various international issues remain uncertain, his attitude toward foreign policy is clear and consistent: He will act unilaterally, using threats to intimidate allies and adversaries, and he will make deals with other tough guys, particularly Putin. Trump believes that by displaying strength he will deter challengers abroad as he has at home, and he expects that he can control the crises he creates to cow opponents and prevent war. He will use bluff, bluster, and even a little “madness” to keep others off balance, to control the international agenda, and, ultimately, to extort maximum benefits for the United States. ...