Congress is considering HR 3166 and S. 1698 also known as the Enemy Expatriation Act, sponsored by Joe Lieberman and Charles Dent. This bill would give the US government the power to strip Americans of their citizenship without being convicted of being “hostile” against the United States.
In other words, you can be stripped of your nationality for “engaging in, or purposefully and materially supporting, hostilities against the United States.” Legally, the term “hostilities” means any conflict subject to the laws of war but considering the fact that the War on Terror is a little ambiguous and encompassing, any action could be labeled as supporting terrorism.
http://www.law.cornell.edu/uscode/8/1481.html
http://www.govtrack.us/congress/billtext.xpd?bill=h112-3166