In an unusually direct speech aimed at members of his own party, Sen. John McCain (R-Ariz.) took to the floor of the Senate on Wednesday to defend a longtime aide and confidant of Secretary of State Hillary Rodham Clinton.

Huma Abedin, a Muslim and the deputy chief of staff and aide to Clinton, has been accused by former presidential candidate Michele Bachmann (Minn.) and four other House Republicans of being connected to a conspiracy theory that the Muslim Brotherhood is trying to infiltrate the highest levels of the U.S. government.

In a letter last month to the State Department’s inspector general requesting an investigation, the House Republicans cited a study from a conservative think tank that said Abedin “has three family members — her late father, mother and her brother — connected to Muslim Brotherhood operatives and/or organizations. Her position affords her routine access to the secretary and to policymaking.”

Around noon, a somber McCain rose in her defense — not just to support a friend but also to take on fringe voices in his own party. It was a familiar role for McCain, who built a reputation as a maverick with a willingness to criticize what he believes are radical views within his party.

In his first bid for the presidency, in 2000, McCain labeled Pat Robertson and Jerry Falwell “agents of intolerance.” And in his 2008 campaign, amid rising conspiracy theories about then-Sen. Barack Obama, McCain took the microphone from a woman at one of his town hall meetings who had called Obama an “Arab.”

Huma Abedin is deputy chief of staff and aide to Secretary of State Hillary Rodham Clinton. (Pablo Martinez Monsivais/AP)

“No ma’am,” McCain said, “he’s a decent family man.”

McCain’s candor has, at times, gotten him in trouble with his own party, although no one, aside from Bachmann, criticized his remarks Wednesday. A spokesman for House Speaker John A. Boehner (R-Ohio) declined to comment, as did most of the others who signed the letter.

“Rarely do I come to the floor of this institution to discuss particular individuals,” McCain said at the beginning of his remarks. “But I understand how painful and injurious it is when a person’s character, reputation and patriotism are attacked without concern for fact or fairness.”

McCain called Abedin a friend and a devoted public servant, and denounced what he called “sinister” accusations. The charges “are nothing less than an unwarranted and unfounded attack on an honorable woman, a dedicated American and a loyal public servant,” McCain said. “These attacks on Huma have no logic, no basis and no merit. And they need to stop now.”

The Arizona senator chastised his fellow Republicans for distorting what it means to be an American.

“This is about who we are as a nation, and who we still aspire to be. . . . When anyone, not least a member of Congress, launches specious and degrading attacks against fellow Americans on the basis of nothing more than fear of who they are and ignorance of what they stand for, it defames the spirit of our nation, and we all grow poorer because of it.”

There was little immediate reaction to the 7.5-minute speech in the otherwise empty Senate chamber, but the attention of Capitol Hill quickly shifted to the House, where lawmakers were taking up a bill about looming defense spending cuts. After a 1:15 p.m. vote, Bachmann darted out of the Speaker’s Lobby and down a flight of stairs, a spokesman shooing reporters away.

In a statement released later, Bachmann said her inquiries “are unfortunately being distorted.”

“The intention of the letters was to outline the serious national security concerns I had and ask for answers to questions regarding the Muslim Brotherhood and other radical groups’ access to top Obama administration officials,” Bachmann said in her statement. “I will not be silent as this administration appeases our enemies instead of telling the truth about the threats our country faces.”

Bachmann and her colleagues — Reps. Trent Franks (Ariz.), Louie Gohmert (Tex.), Thomas J. Rooney (Fla.) and Lynn A. Westmoreland (Ga.) — wrote to the inspectors general of the departments of Homeland Security, Justice and State asking that they investigate the U.S. government’s involvement with the Muslim Brotherhood.

The letter to the State Department mentioned Abedin, citing a Web site maintained by the Center for Security Policy that calls her one of “six Islamist sympathizers” who have “achieved positions within or advisory roles serving Team Obama.”

“I regret that Mrs. Abedin has become the media focus of this story, because the intention of the letters was to bring greater attention to a legitimate national security risk,” Rooney said in a statement.

In an interview following his speech, McCain said he learned about Bachmann’s inquiry two days ago and felt compelled to correct the record. Aides said his remarks were written Tuesday night.

“It’s not as if she’s somebody I ran into, we’ve actually traveled to different places with Secretary Clinton, so we’re close personal friends,” McCain said in an interview. He recalled traveling with Clinton and Abedin to Afghanistan, Iraq, Latvia — even the archipelago of Svalbard near the Arctic Circle.

Abedin has worked for Clinton since her husband was president. For more than a decade she has traveled with Clinton, through two Senate campaigns, the 2008 presidential race and around the world on official diplomatic missions. Her unique perch, usually within arm’s length of Clinton and within the scope of photographers, often puts her in the public eye.

The State Department did not return requests for comment on McCain’s speech.

Abedin, 37, is also known as the wife of former Rep. Anthony Weiner (D-N.Y.), who resigned in disgrace last year after sending inappropriate pictures of himself to women via Twitter.

In an e-mail, Weiner thanked McCain for speaking out.

“My family and I are grateful to Senator McCain,” Weiner said. “I think he spoke for many Americans in expressing his disgust for the charge against my wife.”

Weiner’s name surfaced in recent news reports that suggested he is planning to revive his political career by mounting a campaign next year for mayor of New York. The former congressman has denied those reports.

The speech also came hours after People Magazine published an exclusive interview with Weiner and Abedin about how they weathered his scandal.

“It took a lot of work to get to where we are today, but I want people to know we’re a normal family,” Abedin told the magazine.

“Anthony has spent every day since [the scandal] trying to be the best dad and husband he can be,” she added. “I’m proud to be married to him.”