For many countries in the Middle East, the Arab Spring has proved to be a long and inconclusive season. Popular insurrections in Egypt, Yemen, Syria, and even Libya have yielded deeply ambiguous results. But there is one uprising whose outcome is fairly definitive at this point: Bahrain’s. After massive protests shook the tiny Gulf state last February and March, Bahraini authorities swept in with the backing of foreign troops from Saudi Arabia and the United Arab Emirates, clearing the streets of demonstrators and imposing martial law. Since then, government forces have engaged in a long and ruthless crackdown, effectively burying hopes of real reform. If any Arab Spring revolt can be pronounced a failure thus far, this is it.

Not coincidentally, Bahrain’s ill-fated uprising stands out in another way, too. The United States, which took a forceful stance on other Arab revolts, remained relatively passive in the face of the kingdom’s unrest and crackdown. To many who are familiar with the region, this came as no surprise: of all the Arab states that saw revolts last year, Bahrain is arguably the most closely tied to American strategic interests. The country hosts the U.S. Navy’s 5th Fleet, a key watchdog in some of the world’s busiest oil-shipping lanes, waters that also border Iran. In the past five years, the U.S. has sent close to $100 million in military aide to Bahrain—a hefty amount for such a small country—much of it earmarked for “stabilization operations” that include training and equipping police and paramilitary forces. And Bahrain’s leadership is intimately linked to that of Saudi Arabia, America’s greatest ally in the region.

Since beginning its crackdown, Bahrain’s leadership has been assiduous about molding perceptions of the uprising, retaining major public relations firms like Washington, D.C.’s Qorvis and London’s Bell Pottinger to help shape the narrative that reaches those in the West. On social-media sites like Tw...