Privacy advocates are voicing concerns about a lesser-known point in the much-publicized bipartisan ”Gang of Eight” immigration reform proposal introduced last month.

Key senators are exploring an immigration reform bill that would in part force every citizen and non-citizen U.S. worker to carry a high-tech identity card that would use fingerprints or other personal markers to prove a person’s legal ability to work, The Wall Street Journal reports.

Civil liberties organizations fear this portion of the law could lead to a national identity card that could trace Americans through their daily lives. In addition to the Senate plan, the leaked White House “backup plan” also calls for illegal immigrants to submit biometric information to qualify for a new type of visa.

Chris Calabrese of the American Civil Liberties Union is worried the biometric ID card could eventually be required to board airplanes, purchase a firearm or vote, Fox News reports.

“It becomes in essence a permission slip to do all of the ordinary things that are your rights as an American,” Calabrese says.

The notion of biometric IDs has been talked about before in the immigration debate and supported by five members of the Gang of Eight in the past.

Could these high-tech ID cards split each party down civil libertarians lines and be the straw that breaks the back of this increasingly doomed immigration reform push?

Watch the “Real News” panel debate Thursday on high-tech ID cards: