I like Joe Lieberman and Scott Brown, but their Terrorist Expatriation bill is a very, very bad idea. It would allow the government to strip Americans of their citizenship if it can show by a preponderance of the evidence (not beyond a reasonable doubt) that they provided material support for terrorism.
To lower the evidential bar is a terrible idea on general principles (and is certainly unconstitutional), but it’s particularly troubling in light of the government’s recent behavior in the Hutaree militia case. In that case, it appears that the government arrested several people for nothing more than discussing their fantasies about overthrowing the government. Unless the government has more evidence in reserve, this people will probably go free. But, if the government needed to show only a preponderance of the evidence, that would be another matter entirely. They might be able to make their flimsy case stick.
As Glenn Reynolds argues,
We need a bright-line distinction between citizens and noncitizens to reduce the temptation of political abuse. This blurs that distinction, which is a bad thing.