Sen. Joe Lieberman, D-CT, plans to introduce legislation Thursday that would strip Americans of their citizenship if they affiliate with a foreign terrorist organization and are apprehended abroad. The companion legislation in the House will be offered by Rep. Jason Altmire, D-PA.

The senator, who spoke first to Fox about this on Tuesday, referred to a 1940's era law that states that citizens fighting in a military force that is an enemy of the U.S. renounce their citizenship. "I think it's time to look at whether we want to amend that law to apply it to American citizens who choose to become affiliated with foreign terrorist organizations, whether they should not also be deprived automatically of their citizenship and therefore deprived of rights that come with that citizenship."

Lieberman, according to an aide, plans to amend that law to add those who are part of a terrorist organization. Currently, 8 USC 1481 reads, "A person who is a national of the United States whether by birth or naturalization, shall lose his nationality by voluntarily performing" the following act, among others, "entering, or serving in, the armed forces of a foreign state if such armed forces are engaged in hostilities against the United States."

The aide made clear that the Time Square bombing suspect, Faisal Shahzad, would not be affected by this law, as he was captured on U.S. soil, attempting to board a flight at John F. Kennedy International Airport. But, should a citizen like Shahzad, if found to be part of a foreign terrorist organization, as designated by the State Department, be captured overseas, the person, stripped of citizenship, could then be hauled before a military commission, something the Lieberman aide said would stop "a big show trial in New York City."

The Obama Administration once contemplated a civilian trial in Manhattan for those charged with the attacks of September 11, 2001.

Still, one civil liberties advocate who asked to remain anonymous to candidly discuss a bill that has not yet been introduced, tells Fox, it is difficult to know the membership of amorphous terrorist organizations and "the government often makes mistakes," as it did with hundreds of detainees once imprisoned at Guantanamo. "Part of the problem here is that someone taking up arms against the U.S. by joining a foreign military is a more clear cut case. Either you’re in the foreign military or you're not. And I think that the chances for error and mistake are lower than they would be if the government is trying to decide if you associating yourself with an international terrorist organization."

Lieberman is expected to highlight two other incidents of American citizens abroad who would be hit by this new law, according to the aide: Anwar al-Awlaki, the American Muslim cleric based in Yemen who has been accused of inciting Muslims to take up arms against America and who President Obama recently approved for a targeted assassination. "The Obama Administration has gone further than this bill," the Lieberman aide said, adding, "If Awlaqi can be targeted for assassination, surely his citizenship should be taken away."

Lieberman, at a noon news conference Thursday to introduce the bill, is also expected to cite Adam Gadahn, a 31-year old U.S. citizen now on the FBI's Most Wanted Terrorists list which states, "Gadahn was indicted in the Central District of California for treason and material support to Al Qaeda. The charges are related to Gadahn's alleged involvement in a number of terrorist activities, including providing aid and comfort to Al Qaeda and services for Al Qaeda."

According to the Lieberman bill, Gadahn, who has been seen on You Tube tearing up his U.S. Passport, would be stripped of his citizenship for his affiliation with Al Qaeda, a designated terrorist organization by the State Department.

The civil liberties advocate said a, "To do that with someone who has not been convicted of anything, is an extreme position...It does seem like Lieberman is searching for some way to get an upper hand in a week when the government can claim some success."

Lieberman appeared to be gaining some bipartisan support in the always volatile arena where politics and terrorism collide. Sen. John McCain, R-AZ, praised the legislation, and Sen. Chuck Schumer (D-N.Y.) told the AFP, "That sounds like something I'd support, but I'd have to look at the legislation."

Senate Majority Leader Harry Reid, D-NV, took a cautious approach, though he said the legislation should be examined, "It's something we all need to take look at, but we need to very careful."

Surprisingly, Sen. Lindsey Graham, R-SC, a military lawyer and often a hawkish ally of Lieberman's on national security, said he questions the value of a bill like this. "If you strip people of their citizenship, do you lose the ability to prosecute them for treason? Someone like him could never get the death penalty unless they were tried with treason," Graham said, adding, "I don't want to take off the table the ability to charge someone for treason who's been a citizen who is helping Al Qaeda or the Taliban...The question I have is, do you lose that ability to try them for treason?"

The Lieberman bill would not be retroactive, and anyone stripped of their citizenship, based on a "preponderance of evidence" legal standard, "can challenge that determination in federal court" with that same legal standard, the senator's staffer said.

The aide cited the 1980 Supreme Court case Vance vs. Terrazas, as precedent for the Lieberman bill, in which the court stated that a preponderance of evidence showed that the State Department rightly found that Laurence Terrazas, a dual U.S./Mexican citizen by birth, knowingly renounced his U.S. citizenship by signing a Mexican document that did just that.

Lieberman, according to his aide, hopes that his legislation will deter Americans and those abroad who would seek to recruit them for belligerent purposes.

Lieberman has no plans to go after citizens like Shahzad, according to the aide. "Constitutionally it's more difficult for U.S. citizens on U.S. soil. This is a first step dealing with a non-state actor," the aide said.

"Once you actually look at the facts, it's not that crazy," the aide said to critics of the bill.