The US Senate's most liberal and most conservative member have both come out strongly against the bipartisan compromise on tax cuts between President Barack Obama and Republicans.

Self-avowed democratic socialist Sen. Bernie Sanders (I-VT) on Tuesday evening promised he will "do whatever it takes" to prevent passage of the measure, objecting to its temporary two-year extension of tax cuts for the highest income earners, a centerpiece of the Republican agenda.

A fierce opponent of the high-end tax breaks, Sanders appeared on television Tuesday blasting the deal as a "moral outrage." He depicted it a Republican ploy to hold the middle class "hostage" to the demands of millionaires and billionaires.

Sanders' office confirmed to Raw Story that he will filibuster the measure, becoming the first senator to announce such an intention, and will court others to do the same.

Also on Tuesday, after Obama's prime time pitch depicting the bill as a necessary compromise to move forward, arch-conservative Sen. Jim DeMint (R-SC) said he'll also filibuster to the bill, but for different reasons than Sanders.

DeMint told conservative radio host Hugh Hewitt the deal is inadequate because it doesn't permanently extend the high-end tax cuts, it alters the estate tax for estates valued at over $5 million, and doesn't offset unemployment insurance.

Asked it he would vote for either the measure or the cloture vote to advance it, DeMint responded "no" and "on both counts" -- which amounts to supporting a filibuster.

The deal includes a two-year extension of the Bush-era middle class tax cuts, a decrease in the payroll tax, a 13-month extension of unemployment benefits, and other measures intended to stimulate growth.

Senate Minority Leader Mitch McConnell (R-KY) said Tuesday the deal was "essentially final" and predicted that the "vast majority" of Republicans in the chamber would support it.

Democrats are displeased with the high-end tax cut extension, and may still dissent if the final version contains unacceptable provisions, the Senate's second-ranking Democrat, Dick Durbin (IL), warned.

A poll by Survey USA, commissioned by, found Tuesday that a majority (57 percent) of Obama supporters say this compromise makes them less likely to back Democrats.

The president reiterated his opposition to the top-bracket tax cuts Tuesday, saying that tough political realities forced him to accept them for now but promised he will fight to kill them in 2012, the year of his re-election bid.