Sen. Bernie Sanders (I-Vt.) was one of the first and most vocal opponents of President Obama's tax cut compromise with Republicans, which would extend cuts to all Americans, including the wealthiest.
Thursday, Sanders' opposition gained some momentum when House Democrats voted in caucus not to support the tax package in its current form.
Sanders, an Independent who caucuses with the Democrats, applauded the House Democrats' vote, calling it a "real step forward."
In an appearance on "Washington Unplugged," Sanders told CBS News' Sharyl Attkisson, "We have three weeks left in this year to take the fight to the American people."
"People understand with a $13 trillion national debt, it is absurd, totally absurd to give huge tax breaks, millions of dollars in tax breaks, to the very richest people in this country who are already doing very, very well," Sanders said Thursday.
Sanders called on the president to sit down with Democrats to "negotiate a stronger bill" and to put more pressure on Republicans.
"We've got to put pressure on them [Republicans] for a change, rather than our side compromising all of the time," Sanders said.
Sanders also indicated this deal could be a sign the Bush-era tax cuts for the wealthiest could be made permanent. "Two years from now they're going to be extended again and again and maybe even made permanent," Sanders said.
Watch Sanders' appearance on "Washington Unplugged" in the video to the left. Thursday's webcast also featured Philadelphia Tribune Washington correspondent Charles Ellison.
"Washington Unplugged" airs live daily at 12:30 p.m. ET on CBSNews.com.
Christine Delargy is an associate producer for CBSNews.com. You can read more of her posts here. For more of Washington Unplugged, follow us on Facebook and Twitter.