Today Sen. Joe Lieberman (ID-Conn.) introduced his bill aimed at stripping terrorism suspects of their U.S. citizenship, thereby making them eligible for military tribunals and/or indefinite detention (a proposal I discussed this morning). The Terrorist Expatriation Act would make "engaging in…hostilities against the United States" or "providing material support or resources to a foreign terrorist organization" grounds for revoking someone's citizenship. As with the existing grounds—treason, renouncing one's nationality during a state of war, or serving in the military of a "foreign state" that is engaged in hostilities with the U.S.—the determination would be made by the State Department. Someone stripped of his citizenship could challenge the State Department's decision in federal court, where the government would have to show by "a preponderance of the evidence" that he committed an expatriating act with the intent of relinquishing his citizenship. That standard of proof, which means that the allegation is more likely than not to be true, is much easier to satisfy than proof "beyond a reasonable doubt," which is required for a criminal conviction.

Hence an American accused of ties to terrorism could be stripped of his citizenship without anything like the evidence needed to convict him in federal court. It would not matter whether he was arrested here or abroad, or where his offense allegedly occurred; indeed, an arrest, let alone a conviction, does not seem to be a requirement at all. Once stripped of his citizenship, the suspect could be locked in a military prison indefinitely, with or without a trial by a military tribunal (where he would have fewer due process protections than he would in a civilian court) and regardless of whether he was convicted or acquitted.

By linking his end run around due process to the "material support" statute, Lieberman greatly expands the bill's potential applications. As a case that is currently before the Supreme Court shows, the definition of "material support" is vague and broad—broad enough to cover pure speech advocating legal activity, among other things that fall far short of leaving a car bomb in Times Square. Depending on how much evidence of an intent to relinquish citizenship is required, combining the wide net of "material support" with the preponderance-of-evidence standard could easily lead to indefinite military detention of Americans whose links to groups on the State Department's list of foreign terrorist organizations are tenuous, innocent, or even nonexistent.

Lieberman's bill, which is co-sponsored by Sen. Scott Brown (R-Mass.), is here (PDF). His summary is here. Reps. Jason Altmire (D-Pa.) and Charlie Dent (R-Pa.) have introduced the same bill in the House.