Of course we do. A Republican felon (wearing a leg transmitter) was admitted into the Congress in 1998. Marion Barry...gee there are quite a few. And "foreigners" are certainly allowed to run for public office once they have been naturalized. One does not have to be born in the U.S. to run for public office. Where do you get your information anyway?
Naturalized citizens aren't "foreigners." Libertarian candidates are amusing.