While the world was gripped by last weekend’s revelation that U.S. forces had secretly taken down Osama bin Laden, another covert operation was being carried out by armed security personnel — in the service of a key Middle Eastern ally of the United States.

Just after 8 p.m. on May 1, 35-year-old Bahraini opposition politician Matar Ebrahim Ali Matar was home with his wife when the phone rang. A woman who would not identify herself said that she had important documents she urgently needed to give him.

Matar is one of 18 members of the al-Wefaq political party who recently resigned from parliament in protest of the Sunni regime’s crackdown on predominantly Shiite protesters. Constant regime surveillance had become the norm and party leaders feared for their safety, according to one of Matar’s colleagues. Matar suggested the caller meet him at al-Wefaq’s bustling office. She demurred, suggesting an alternative location close to his home.

Matar eventually agreed and drove with his wife to the appointed place. When they arrived, armed, masked men pulled Matar into their car and sped off, according to Matar’s colleague, who is in touch with his wife. Matar has not been heard from since, but a government spokesperson confirmed to one of us that he “has been called in for investigation.”

It has now emerged that another Wefaq member and former parliamentarian, Jawad Fairuz, was arrested the same night in what appears to have been a simultaneous operation. His house was surrounded by some 30 masked agents, weapons drawn, said a source close to his family.

“This is the type of regime we are dealing with. Crackdown and punishment and revenge are the only tools they are using,” said Matar’s colleague. “[Matar is] a very peaceful person, and a politician, doing his job. Who knows? Maybe I will be next.”

Since pro-democracy demonstrations began in Bahrain in February, more than 30 protesters have been killed, according to press reports. The U.S. State Department has condemned the arrest of opposition leaders to little effect. Bahrain’s justice minister announced Tuesday that some 50 doctors and nurses arrested for treating injured protesters will be charged with acting against the state and tried in a military court.

The United States has a particular obligation to try to help Matar. In 2008, he traveled here under the State Department’s Leaders for Democracy Fellowship Program, the flagship of President George W. Bush’s Middle East Partnership Initiative. The program seeks to impart practical organizing tools and a deeper understanding of democracy to emerging civic leaders.

In a meeting with then-Secretary of State Condoleezza Rice, Matar raised his views about representative democracy in Bahrain and his concern that Washington has given the kingdom’s ruling family a pass in exchange for hosting the U.S. Navy’s 5th Fleet’s large base that supports the war in Afghanistan. After the program ended, Matar returned home and focused on getting elected to Bahrain’s parliament.

When Secretary of State Hillary Clinton held a “town hall” in Bahrain in December, Matar raked her over the coals, citing the arrests of lawyers and rights activists. He asked Clinton to use America’s influence to reverse a sharp decline in civil rights in the kingdom, where King Hamad bin Isa al-Khalifa and Bahrain’s ruling Sunni elite preside over a population that is nearly 70 percent Shiite. “Sometime we feel that there are no red lines or constraints between United States and their allies,” he said, according to a transcript of the meeting.

Clinton counseled patience: “I know when you’re in the midst of societies that are as dynamic as Bahrain is, with so many changes happening, that it’s easy to be very focused internally and see the glass as half empty. I see the glass as half full. . . [A]s I’ve said many times already this afternoon, nothing is perfect . . . there’s a lot of work that still lies ahead.”

Three months later, thousands of predominantly Shiite protesters, inspired by other Arab uprisings, flowed into the Pearl Roundabout in the capital of Manama. Government security forces fired buckshot and live bullets into the crowd, killing seven and wounding scores. Demonstrators remained in the square until March, when Saudi-led troops deployed to Bahrain and security forces cleared the roundabout and destroyed its iconic Pearl Monument.

This spring Matar and his political colleagues engaged in negotiations with Crown Prince Salman bin Hamad bin Isa al-Khalifa, who was publicly promising reforms and took pains to play down Sunni-Shiite tensions, casting the attack on the unarmed protesters as “a national tragedy” with no clear antagonists.

Privately, however, the monarchy saw the battle lines more clearly. A high-ranking member of the royal family, interviewed in his home in February, referred to his country’s Shiites almost en masse as agents of neighboring Iran bent on toppling the monarchy. “They’ve always spray-painted ‘Death to Khalifa’ in their villages,” he said. “We don’t care about that — our people go around and spray over before any Sunni can see. But now they’re spraying ‘Death to Khalifa’ right in the Pearl Roundabout, in front of the news cameras! The crack between us has never been wider.”

The arrests have put a deep chill over the opposition movement, as tension rules in the tiny kingdom.

“It’s a rough position to be in for us,” said an American administrator of the Leaders for Democracy Fellowship Program. “We bring people to the U.S. to explore opportunities for democracy, and some end up in trouble for pursuing them once they get home.”

Matar took to heart the American example of democracy and due process — and challenged the United States to live up to its rhetoric in courageous exchanges with two secretaries of state. Washington should do more to meet the challenge his case represents, finding a bolder balance in pursuing our national interests and affronts to human rights.

Michael Bronner is a freelance writer. John Farmer Jr., the dean of Rutgers Law School, was senior counsel on the Sept. 11 commission. They are co-authoring a book on how the Obama administration’s counterterror policy is evolving amid the Arab Spring.