A bipartisan group of lawmakers unveiled a bill Thursday to strip U.S. terror suspects of their citizenship, expressing hope that it could win broad support in Congress.

Sens. Joe Lieberman (I-Conn.) and Scott Brown (R-Mass.), joined by Reps. Jason Altmire (D-Pa.) and Charlie Dent (R-Pa.), released their controversial bill that would add to an existing administrative process and allow federal officials to strip an American accused of joining a foreign terrorist organization of their citizenship.

"For me, part of the value of what we're trying to do here is prevention, not just punishment," Lieberman said Thursday at the Capitol. "For me, that prevention is a most important element of what we're trying to do here."

The bill would add to existing federal law which designates seven categories of acts for which U.S. citizens can lose their citizenship. The bill in question would add another category including those who join or materially support a Foreign Terrorist Organization (FTO), as designated by the secretary of State.

Individuals designated by the State Department as having joined a FTO would be stripped of their citizenship under the existing process, which was upheld as constitutional by the Supreme Court in 1980. People whose citizenship has been stripped could challenge that in the State Department, or in federal district court.

The idea behind the proposal would be to allow the U.S. government to strip citizenship of individuals in order to remove privileges of citizenship -- like access to a passport -- that might facilitate an attack. The bill would also give the government greater leeway in trying American suspects who lose their citizenship in military tribunals, where they don't enjoy the full rights of U.S. citizens in criminal court.

But the plan, details of which first emerged earlier this week in the wake of an attempted car bombing in Times Square, had drawn mixed reactions from Democrats and Republicans in the House and Senate.

House Speaker Nancy Pelosi (D-Calif.) expressed openness to the idea on Thursday, saying she liked the "spirit" of the proposal, but would have to see the specifics.

Lieberman said he hadn't really had a chance to talk with fellow senators, including leadership, but said he hoped to meet with Obama administration officials and military leaders as they push forward with the measure. The Connecticut Independent said he expected the measure would be referred to the Senate Armed Services Committee, though he warned he and Brown reserved the right to offer it as an amendment at some point in the future.

Still, Brown said he expected a number of colleagues to show interest in the proposal.

"I have a feeling that a lot of our colleagues feel the same," he said.

The bill's sponsors sought to frame their legislation in historical context, saying that it simply added to existing rules, but updated them to reflect the realities of war in the 21st century.

Lieberman and the bill's other sponsors in the House and Senate sought to emphasize the bill's historic context, and urged bipartisan action.

"Over the past several years, the threat from Islamist terrorist organizations like al-Qaeda has changed," Lieberman said.

"This is not a partisan issue, as evidenced by the fact that I'm standing up here," Brown said during a press conference unveiling the bill at the Capitol. "I'm asking the administration to look at this in the spirit it's delivered -- in a bipartisan, bicameral way."

"I think it's impossible to overstate the caution we used in putting this bill together," said Rep. Jason Altmire (D-Pa.).

This bill also, Lieberman said, could not be used against Faisal Shahzad, the 30-year-old, naturalized American citizen who is accused of having planted the Times Square bomb.