The list goes on: Richard Nixon’s opening to China in 1972 tilted the balance of power in our favor and helped smooth the United States’ exit from Vietnam; Jimmy Carter’s stewardship of the Egyptian-Israeli peace treaty ended a conflict that had produced four wars since 1948. Adroit diplomacy managed the collapse of the Soviet Union and the reunification of Germany. More recently, patient negotiations led to an agreement with Iran that reversed its progress toward a nuclear bomb.

Mr. Trump’s deference to the military, meanwhile, is hard to square with its track record. The United States had more than half a million troops in Vietnam at the peak of the war and still lost. The 1991 Persian Gulf war was a short-term triumph but did not yield a stable peace. The 2003 invasion of Iraq led to a costly quagmire, to enhanced Iranian influence and, eventually, to the creation of the Islamic State. The American military has been fighting in Afghanistan for nearly 16 years, and the Taliban today controls more territory than at any time since 2001. United States airstrikes helped drive Muammar el-Qaddafi from power in Libya in 2011, and the country is now a failed state.

These campaigns were unsuccessful not because the Pentagon lacked resources, or our soldiers lacked valor or our generals don’t know how to lead. They failed because the United States’ leaders either picked the wrong fights or could not translate battlefield successes into political solutions. Unmatched military might means little unless it is wedded to realistic political goals and effective diplomacy.

To be sure, military strength can facilitate diplomatic success. As George Kennan once observed, “you have no idea how much it contributes to the general politeness and pleasantness of diplomacy when you have a little quiet force in the background.” But bludgeoning others into doing our bidding is not diplomacy. Diplomacy is first and foremost about reaching mutually beneficial arrangements that others will accept and not look to overturn.

Paradoxically, the stronger we are, the more important diplomacy becomes. America’s vast power makes even its closest allies nervous, and diplomacy is needed to assuage others’ concerns and persuade them to follow our lead. Doing this requires officials with a sophisticated knowledge of other states’ interests, a keen appreciation for how America’s actions are perceived and the awareness that even weaker opponents have the ability to resist if we cannot persuade them. That is why Secretary of Defense James Mattis once bluntly warned, “If you don’t fully fund the State Department, then I need to buy more ammunition.”