WASHINGTON – As Democrats and Republicans battle over how much spending should be cut to bridge the budget shortfall, one senator is focusing on the other side of the equation: revenues.

Sen. Bernie Sanders (I-VT) on Thursday afternoon introduced a bill (pdf) that would establish a surtax on millionaires and strip tax deductions for oil companies -- a proposal he claims would cut the deficit by about $50 billion.

The Emergency Deficit Reduction Act would accomplish this by raising taxes by 5.4 percent on annual income over $1 million.

Congress has yet to pass a budget to fund the government for fiscal 2011, approving three continuing resolutions to avoid a shutdown. The latest expires March 18. The Senate rejected the Democratic and Republican proposals Wednesday.

A NBC/Wall Street Journal poll found late February that 81 percent of Americans believe a surtax on millionaires is an acceptable way to close the budget shortfall.

Yet in Congress, the quest is a lonely one. Though leaders of both parties admit the deficit is a pressing problem, none have advanced tax increases to trim the gap. And the outspoken Vermonter isn't pulling any punches.

Republicans, Sanders fumed, want to balance the budget "solely on the backs of the middle class and some of the most vulnerable people in this country." Democrats, he added, aren't "serious" about deficits if they ignore revenues.