From NBC's Ken Strickland
The Senate is expected to vote Tuesday on two competing versions of bills to fund the government for the rest of this year.
Neither bill is expected to get the 60 votes required to advance, but the votes will set the stage for additional negotiations.
The Republican bill is the one already passed by the House, cutting $61-billion from current spending levels. The Senate Democrats' version cuts spending about $6-billion.
The exact timing of the votes hasn't been set, but will likely be mid-afternoon, according to Democratic and Republican aides.
With both bills widely predicted to fail, the only suspense is whether either of the party's moderates will break ranks.
Do moderate Republicans like Collins, Snowe, Brown, or Kirk feel the House bill's cuts are too much and would adversely affect economic growth? Do moderate Democrats like McCaskill, Tester, Manchin, or Ben Nelson think their party's bill doesn't cut spending enough?
Later today in a speech on the Senate floor, Democratic Sen. Joe Manchin will announce he'll vote against both bills, saying they are "extremely partisan and unrealistic." He'll also call for President Barack Obama to step up his efforts to negotiate a compromise.
In excerpts of his speech provided to NBC News, Manchin -- who is up for re-election in 2012 -- says the Democratic bill "doesn't go nearly far enough" and the GOP bill "blindly hacks the budget with no sense of our priorities or of our values as a country."
"The truth of the matter is that this debate, as important as it is, will not be decided by House Republicans and Senate Democrats negotiating with each other - or past each other. This debate will be decided when the President leads these tough negotiations," he will say. "And, right now - that is not happening."
Last week, Vice President Biden held closed-door negotiations with the bipartisan leadership of the House and Senate. And with Biden traveling overseas this week, the White House says negotiations are continuing at the staff level.
The current bill funding government operations runs out March 18th. If a compromise can't be reached by then, Congress and the White House confront a familiar dilemma: pass a short term bill as Congress did last week or face a government shutdown.
"The bottom line is this - the President is the leader of this great nation," Manchin will say. "And when it comes to an issue of significant national importance, the President must lead. Not the Majority Leader or Speaker, but the President."