WASHINGTON - U.S. Rep. Michele Bachmann is facing a public firestorm over her accusations that the Muslim Brotherhood is infiltrating the federal government and working for "America's demise."

Her attacks, including one directed at Huma Abedin, an aide to Secretary of State Hillary Rodham Clinton, prompted Sen. John McCain, the 2008 Republican nominee for president, to denounce her from the Senate floor on Wednesday, where he defended Abedin and called Bachmann's comments "specious and degrading."

The State Department also weighed in, saying Bachmann's remarks were "vicious and disgusting lies."

Bachmann's public campaign against radical Islamic influence in American life has been building for weeks, starting with a series of letters to oversight agencies at five federal departments. In them, she requested formal investigations into what she says are "influence operations" by the Muslim Brotherhood, an Islamic political organization.

The third-term Republican congresswoman, who has been challenged to produce specific evidence for her allegations, so far has gotten a cool response from agency heads. Meanwhile, she's being accused by some of launching a McCarthy-style witch hunt against Muslim-Americans, with her former presidential campaign manager, Ed Rollins, among them. Rollins on Wednesday said Bachmann was guilty of a "grievous lack of judgment and reckless behavior."

Despite the backlash, Bachmann doubled down on her efforts Wednesday, alleging that the Obama administration "appeases our enemies instead of telling the truth about the threats our country faces."

Bachmann has long been a lightning rod of criticism from the left, but her public campaign against what she calls a "deep penetration" into government circles by Islamic radical groups is being met with denunciations from both sides of the political aisle.

Minnesota Democrat Keith Ellison, the first Muslim in Congress, went on CNN Tuesday night to fire back at Bachmann just as she was warning of the dangers of the Muslim Brotherhood and the Obama administration in a speech at a Washington summit of Christians United for Israel, a pro-Israel evangelical group.

"This is McCarthyism at its worst," Ellison told the Star Tribune on Wednesday, referring to the late Sen. Joe McCarthy, whose name became synonymous in the 1950s with his accusations of Communist infiltration in all walks of American life. "This is one of those moments when you can't stay silent," Ellison said.

'They need to stop now'

During the 2008 presidential campaign, Bachmann questioned Obama's "anti-American" associations in a television interview with MSNBC host Chris Matthews. But this is the first time she has questioned the loyalty of a specific individual in Obama's administration, warning that Abedin has "routine access to the secretary and to policy-making."

McCain defended Abedin in personal terms, calling her a "hard-working and loyal servant of our country and our government.

"These attacks on Huma have no logic, no basis and no merit," McCain said. "They need to stop now."

In a letter to Bachmann on Wednesday, Ellison demanded a "full accounting" of the sources of her allegations.

Bachmann's letters, sent June 13, cite research by a group called the Center for Security Policy, founded by Frank Gaffney, a controversial figure who has feuded with figures of the left and right, including conservative icon Grover Norquist, who accused him of bigotry.

Gaffney, who writes widely about the threat of sharia, or Islamic law, in the United States, has said he was an informal foreign policy consultant in Bachmann's presidential bid.

Bachmann's letters were sent to the inspector general offices of the Departments of State, Justice, Defense, Homeland Security, and the Office of the Director of National Intelligence.

They were also signed by Republican Reps. Louie Gohmert (Texas), Trent Franks (Ariz.), Thomas Rooney (Fla.) and Lynn Westmoreland (Ga).

Using nearly identical language, all warn of government policies "that appear to be a result of influence operations conducted by individuals and organizations associated with the Muslim Brotherhood."

The letter to the State Department warns of Abedin's family connections to the Muslim Brotherhood, including "her late father, her mother and her brother."

Abedin, of mixed Indian and Pakistani heritage, is married to former New York Congressman Anthony Weiner, who is Jewish.

In a written reply to Ellison, Bachmann said her inquiry "is not a question of singling out Ms. Abedin." But, she added, "I am particularly interested in exactly how ... she was able to avoid being disqualified for a security clearance."

In her letter to the State Department inspector general, Bachmann also questioned diplomatic initiatives "engaging" the newly elected Muslim Brotherhood leaders in Egypt and foreign aid grants to the Palestinian Authority, which she said benefits radical groups such as Hamas and Fatah.

'Christian patriots'

A separate Bachmann letter criticizes Justice Department outreach efforts to Muslim groups in the United States, as well as its "priority" on investigating bias crimes against "Muslims, Sikhs, and people of Arab and South Asian descent."

Bachmann's complaint against the Homeland Security Department faults officials there for equating jihadist threats with those posed by "Christian patriots," "Constitutionalists" and "militia extremists." At the Pentagon, she said, officials failed to "characterize accurately the jihadist motivations" of Maj. Nidal Hasan, accused of the 2009 shooting rampage at Fort Hood in Texas.

Doug Welty, a spokesman for the State Department's inspector general office, said Bachmann's complaint appears focused on foreign policy differences with the Obama administration rather than on the effectiveness of programs or misuse of government funds. "It's really outside of our mandate," he said.

The response has been equally cool elsewhere. The inspector general office for the Department of Homeland Security, for example, told the Star Tribune it will not pursue Bachmann's allegations, citing "budgetary restraints."

Bachmann also took issue with National Intelligence Director James Clapper, who told Congress last year that the Muslim Brotherhood in Egypt is "very heterogeneous [and] largely secular."

At Tuesday's Christians United summit, Bachmann laid out the biblical underpinnings of her views on the Middle East, recounting a "legend" about angels asking if the blessings bestowed on the Israelites might be "too generous."

"Not really," God said, according to Bachmann's telling. "Just wait and see the neighbors I'm about to give them."

Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.