The Trump administration’s rebalancing of priorities away from such considerations is apparent in the White House’s budget proposal for 2018. The president has asked Congress for a $52 billion increase in the Pentagon’s budget, to be paid for, in part, by slashing nearly $26 billion from the budget for diplomacy and foreign aid next year — a 28 percent reduction from 2017.

As my colleague Helene Cooper reported, African generals and American military experts are worried that the United States has lost interest in promoting development in Africa and is focusing nearly exclusively on military cooperation.

The Trump administration has proposed cutting one-fifth of the funds used for buying antiretroviral drugs for people infected with H.I.V., a program that has saved hundreds of thousands of lives on the continent. It has pulled out of an agreement to help finance efforts by poor nations in Africa and elsewhere to deal with radical climate change. In contrast, funding for military training programs, joint exercises and antiterrorism initiatives is expected to increase.

And Mr. Trump’s stand on trade — threatening to encircle the United States with a wall of punitive tariffs and other protections (ironically justifying protectionism on grounds of national security) — is likely to be more damaging to global development than his stand on aid, further weakening an already wobbly commitment by the world’s largest nations to refrain from protectionist measures that would stymie global growth.

As Simon Evenett of the University of St. Gallen in Switzerland noted, American policy has become markedly more protectionist this year, bucking a trend of decreasing protectionism among the world’s large economies.

Washington’s interest in global development has never been more than lukewarm, despite arguments about its strategic benefits. American foreign aid is paltry, adding up to 0.18 percent of its national income last year, according to the Organization for Economic Cooperation and Development, far below that of other wealthy countries. But that’s roughly twice the share achieved in 1997.

Still, the America First rhetoric from the Trump administration justifies the suspicion among the world’s poorest nations that the United States has lost interest for real. The United States — against the advice of its generals — has become indifferent to whether the developing world develops or not. It may even be turning into a promoter of underdevelopment.