Winning! It’s the White House watchword when it comes to the US armed forces. “We will give our military the tools you need to prevent war and, if required, to fight war and only do one thing—you know what that is? Win! Win!” President Donald Trump exclaimed earlier this year while standing aboard the new aircraft carrier USS Gerald R. Ford.

Since World War II, however, neither preventing nor winning wars have been among America’s strong suits. The nation has instead been embroiled in serial conflicts and interventions in which victories have been remarkably scarce, a trend that has only accelerated in the post-9/11 era. From Afghanistan to Iraq, Somalia to the Philippines, Libya to Yemen, military investments—in lives and tax dollars—have been costly and enduring victories essentially nonexistent.

But Amadou Sanogo is something of a rare all-American military success story, even if he isn’t American and his success was fleeting. Sanogo learned English in Texas, received instruction from US Marines in Virginia, took his intelligence training in Arizona, and underwent Army infantry officer basic training in Georgia. Back home in his native Mali, the young army officer was reportedly much admired for his sojourn, studies, and training in the United States.

In March 2012, Sanogo put his popularity and skills to use when he led a coup that overthrew Mali’s elected government. “America is [a] great country with a fantastic army. I tried to put all the things I learned there into practice here,” he told Der Spiegel during his tenure as Mali’s military strongman. (He eventually lost his grip on power, was arrested, and in 2016 went on trial for “complicity in kidnapping and assassination.”)

Since 9/11, the United States has spent more than $250 billion training foreign military and police personnel like Sanogo. Year after year, a sprawling network of US programs provides 200,000 of these soldiers and security officers with assistance and support. In 2015, almost 80,000 of them, hailing from 154 countries, received what’s formally known as Foreign Military Training (FMT). ...