President Trump’s recently released budget proposal — an early version that Washington dubs “the skinny budget” — fattens the military while whacking 28 percent from the State Department and the Agency for International Development (USAID). The president’s proposal, said Office of Management and Budget Director Mick Mulvaney, is a “hard-power budget, not a soft-power budget.”

But defense and diplomacy are not binary, but rather complementary components — along with development — of an effective foreign policy.

That’s not just the thought of diplomats, but most military leaders, including more than 120 who retired as three- or four-star generals or equivalent rank from all branches of the armed forces who recently wrote to congressional leaders to “share our strong conviction that elevating and strengthening diplomacy and development alongside defense are critical to keeping America safe.”

The letter continues: “We know from our service in uniform that many of the crises our nation faces do not have military solutions alone.” Listing the need to confront violent extremism, prevent pandemics, stabilize fragile states and deal with the postwar record 65 million displaced people worldwide, the leaders say that the State Department, USAID, Millennium Challenge Corporation, Peace Corps and other development agencies are “critical to preventing conflict and reducing the need to put our men and women in uniform in harm’s way.”

The letter then quotes Defense Secretary Jim Mattis, who said when he was commander of U.S. Central Command: “If you don’t fully fund the State Department, then I need to buy more ammunition.”

The United States, and indeed the world, has plenty of ammunition. And while there are no silver bullets for the crises buffeting every continent, diplomacy and development are key to keeping the U.S. from yet more warfare — an objective clearly stated by then-candidate Trump.

Of course, defensive alliances are crucial, too, especially in a Europe increasingly destabilized by Russian aggression. That’s why it’s good to hear that Secretary of State Rex Tillerson will attend a rescheduled meeting of NATO foreign ministers, after initially declining due to a poorly scheduled summit between Trump and Chinese President Xi Jinping, as well as a subsequent trip to Moscow. And it’s an encouraging signal that Trump has announced that he will attend a NATO summit in Brussels in May.

“American strength and American security are based on two things: our military power and our diplomatic power,” Nicholas Burns, a former U.S. ambassador to NATO who now leads the Future of Diplomacy Project at Harvard, told an editorial writer. “The vast majority of our efforts to protect ourselves and advance our interests are done by diplomats. … The generals and admirals know that the way to prevent the United States military from being overused is to help the diplomats solve the problems before we need to call in the military.”