Mark Kirkorian beat me to the headline, but it was too obvious to go unused; Michelle Bachmann and her family are now Swiss citizens as well as US citizens. Her husband is of Swiss descent and they took advantage of that "loophole." I'm not sure what advantages that might have, other than allowing use of a Swiss passport that would let you visit Cuba or other places that are on poor terms with Foggy Bottom.
Kirkorian, the Corner's resident immigration hawk, doesn't like it, and that's not an uncommon response. Politicians with dual citizenship are looked at askance for questionable loyalties.
A Canadian case is new NDP leader Thomas Mulcair's French co-citizenship via his French-born wife. He was in position to congratulate fellow lefty François Holland's win as a fellow Frenchman. Mulcair and former Liberal leader Stephane Dion have gotten flak for their literal French-Canadian legal status.
I doubt that Congresswoman Bachmann will have a bias towards cutting the Swiss slack on banking policy due to this new status. It almost seems like a flag of convenience, like companies setting up shop in Delaware for their loose corporate governance laws or ships flying Panama or Liberia's flag for their light regulation on shipping.
I'm the uncle of three dual-citizens; they're being raised here and will likely be as American as I am but likely a bit less American than the gung-ho nationalist Bachmann. I wouldn't be fearful of her becoming a pacifist, isolationist Swiss fifth column.