Before Minnesota Republican Michele Bachmann went on a nationally syndicated radio program accusing congressional colleague Keith Ellison, D-Minn., of ties to the Muslim Brotherhood, there was an exchange of letters.

The first was Ellison's letter of July 12, asking that Bachmann document her recent allegations about radical Islamic infiltration in the U.S. government. He particularly wanted to know why Bachmann had singled out Huma Abedin, a top aide to Secretary of State Hillary Rodham Clinton.

Bachmann's reply came the next day. Beginning, "Dear Representative Ellison" it went on for 16 pages and 59 footnotes. Nowhere did it mention her suspicions about Ellison's alleged ties to the Muslim Brotherhood, a group she believes is intent on "America's demise."

Her letter closed politely by thanking Ellison and offering to "revisit" the issue once she got the answers to all her questions.

"It is my intention to wait for the investigations to be completed to comment further," Bachmann wrote.

Except she didn't wait. On Thursday, six days later, she went on Glenn Beck's radio show and accused Ellison of having "a long record of being associated with CAIR [the Council on American-Islamic Relations] and with the Muslim Brotherhood."

Ellison didn't feign surprise. "I knew that sooner or later she would get around to accusing me," he said.

Until then, Ellison added, he had been trying to stick up for Abedin, a fellow Muslim who he felt was being maligned on the basis of discredited sources and guilt by association.

Said Bachmann to Beck: "All we're doing is asking a question."

But in her original request for an investigation into Islamic "influence operations" in the federal government, Bachmann cited Abedin as an "example" of the concerns she was raising. Abedin, she said, "has three family members -- her late father, her mother and her brother -- connected to Muslim Brotherhood operatives and/or organizations."

She also noted that Abedin's position as Clinton's deputy chief of staff "affords her routine access to the secretary and policy-making."

In her subsequent letter to Ellison, Bachmann cited as evidence reports in Arab-language media, including Al-Jazeera. She also cited a 2002 law review article that referenced Abedin's father, who died two decades ago, as a founder of the Institute of Muslim Minority Affairs in Saudi Arabia. That group allegedly had "quiet" but unspecified support of the then-general secretary of the Muslim World League, a group with "a longtime history of being closely aligned" with the Muslim Brotherhood.

In a letter back to Bachmann the day before she denounced him on Beck's program, Ellison wrote, "In making this connection, which is five times removed from Ms. Abedin, you engage in guilt by association."

It was the same day that Arizona Sen. John McCain and other leading GOP figures in Congress started to line up in defense of Abedin, a well-respected official of mixed Indian and Pakistani descent.

Bachmann's office hasn't been returning calls and e-mails from the Star Tribune all week. But she has shown no signs of backing down in the face of the bipartisan blowback -- other than to suggest that she really didn't accuse Abedin of anything.

She had written to Ellison that it's "not a question of singling out Ms. Abedin." But she still wanted to know "how ... she was able to avoid being disqualified for a security clearance."