THE RULERS of Bahrain, an island nation in the Persian Gulf that hosts the U.S. 5th Fleet, undoubtedly worry that their harsh crackdown on a peaceful pro-democracy movement could damage vital relations with Washington. The government has hired a pricey Washington lobbying firm and regularly dispatches senior officials to stroke the administration and Congress. It has repeatedly promised to free political prisoners, reverse a mass purge of suspected protesters from government jobs and negotiate meaningful reforms of the al-Khalifa monarchy, a Sunni dynasty that rules over a majority-Shiite population.

Yet the regime hasn’t kept its promises — and its unjustified and self-defeating repression goes on. The latest brazen step came Thursday, when a special security court sentenced 20 doctors and other medical professionals to lengthy prison terms after a grossly unfair trial. The doctors were charged with stockpiling weapons and trying to overthrow the regime; in fact, their offense was treating injured protesters who arrived at their hospital and reporting what they saw to international media. A host of human rights groups, including Human Rights Watch and Amnesty International, pronounced the trial a travesty; Human Rights First said the medics had given “consistent and credible accounts of being tortured into giving confessions.”

The convictions came just a day after a court upheld the convictions of 21 opposition leaders, including clerics, members of political parties, human rights activists and bloggers. None are guilty of violence, but all were nonetheless accused of terrorism; eight received life sentences. They, too, have offered credible reports of torture. Another human rights group, Freedom House, said the rulings continued “a pattern of repression that belies any promises of meaningful reform by the government.”

Such a unanimous verdict from human rights groups ought to spell trouble for a government that depends on the United States for defense and enjoys a free-trade agreement with it. Yet there is no sign of serious friction between the Obama administration and the al-Khalifa family. Administration spokesmen have largely kept quiet as the crackdown has proceeded. On the military front, it is business as usual. This month the Pentagon notified Congress of a plan to sell Bahrain armored Humvees and anti-tank missiles worth $53 million.

The message this sends is unmistakable: The regime’s crackdown will not affect its cozy relationship with the United States. This is dangerous for the United States as well as for Bahrain, because the government’s attempt to suppress legitimate demands for change from a majority of the population is ultimately doomed to failure. Bahrain’s ruling family should be given more reason to worry about its standing in Washington. A congressional hold on the arms package would be a good way to start.