U.S. Rep. Michele Bachmann often plunges recklessly into controversy, but her latest sally is most damaging: an attack on the reputations of an individual and five federal-government departments.

The Minnesota congresswoman says the Muslim Brotherhood has infiltrated the departments and is working internally for the demise of the United States. Bachmann singled out Huma Abedin, an aide to Secretary of State Hillary Rodham Clinton, saying members of her family had ties to the Muslim Brotherhood, which is dedicated to spreading Islamic law. Some of its members have been linked to terrorist groups.

Bachmann’s claims are unsupported by any specific information, and she offers no proof that Abedin has anything to do with the Muslim Brotherhood. The only plausible speculation for why Abedin comes under attack is that she is Muslim, born in the United States of Indian and Pakistani heritage.

Bachmann’s latest misadventure has drawn rebukes from U.S. Sen. John McCain, who called Bachmann’s remarks “specious and degrading.” The State Department tagged them “vicious and disgusting lies.”

While Abedin’s 20 years of public service should save her reputation from assaults by an unthinking zealot who once equated the national debt to the Holocaust, Bachmann’s latest actions deserve the same censure in Congress that Joseph McCarthy received for his witch hunt for Communists 60 years ago.