Bangladesh, Sept. 24 -- Most Americans would struggle to locate Myanmar on a map, let alone its northernmost state of Kachin. Yet this rugged, mountainous frontier—wedged between China and India—has once again emerged as a geopolitical flashpoint. For Washingtons strategists, it looks like an opportunity: a region where old alliances, mineral wealth, and Chinese vulnerabilities converge. For anyone with a sense of history, however, it is also a reminder of how the United States tends to wade into other peoples wars, misread local complexities, and leave behind wreckage more enduring than its promises.

The US has a history in Kachin, though it is one most Americans have long forgotten. During World War II, the Office of Strate...