From NBC's Ken Strickland and Carrie Dann
As of this morning, the Senate was expected to vote on two competing government funding bills – one Republican-backed measure that would cut $61 billion from current spending levels, and one sponsored by Democrats that would cut far less.

Now, it looks like that vote may not happen until tomorrow, and both sides are pointing fingers over the delay.

What happened?

Senate Majority Leader Harry Reid claims that Republican leader Mitch McConnell reneged on a deal the leaders reached with Vice President Joe Biden last week to have up-or-down votes on both measures.

“We agreed to hold a vote on the Republican plan … and then vote on the Democratic plan, which makes much smarter cuts and more solid investments.  Then we would return to the negotiating table and try again to find common ground,” Reid fumed on the Senate floor Tuesday morning.  

Now, he says, Republicans “don’t want to vote on their own bill.”

Republicans push back hard on that claim, saying the vote will happen -- either today or tomorrow -- but that the Senate has to finish a pending patent reform bill first.

Democrats say privately that McConnell doesn't want to take the vote until he can be assured that he won't have any defections on the GOP-House passed bill. That measure would cut about $61-billion in spending, which could be a tough pill to swallow for some moderate Republicans wary of the cuts' effects on the economy.

Several GOP aides tell NBC News that the vote will be "very tough" for some GOP members who have remained officially "undecided" on how they'd vote on the House bill.

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."

NBC’s Ken Strickland reports: The Senate is expected to vote today two competing versions of bills that fund the government for the rest of this year. The exact timing of the votes hasn't been set, but will likely be mid-afternoon according to Democratic and Republican aides. Neither bill is expected to get the 60 votes required to advance, but will set the stage for addition negotiations. The Republican bill is the one already passed by the House, cutting spending by roughly $61 billion from current levels. The Senate Democrats' version cuts spending by about $6 billion.

The Hill: "After losing round one of the budget battle last week, Democrats are hoping that the votes will represent a turning point in the budget talks. The competing bills have little chance of attracting the necessary 60 votes for passage, but Democrats are hopeful they’ll get more yes votes than the GOP. If that happens, Democrats argue, Republicans need to come closer to their budget-cutting number."

But Democrat Joe Manchin (WV) doesn't like the idea and he's going to criticize President Obama for lacking leadership on the budget negotiations. He'll deliver today a tough floor speech criticizing both parties and the idea of holding the votes at all.

"Why are we engaging in this political theater?" Manchin is expected to say, according to prepared remarks. "Why are we voting on partisan proposals that we know will fail, that we all know don’t balance our nation’s priorities with the need to get our fiscal house in order? Why are we doing all this when the most powerful person in these negotiations - our President - has failed to lead this debate or offer a serious proposal for spending and cuts that he would be willing to fight for? … 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. And, right now -- that is not happening."

From NBC’s Mark Murray, Domenico Montanaro, and Ken Strickland
Republican Sen. John Ensign will hold a news conference at 3pm ET in Nevada to discuss "his political future," his office announced today

*** UPDATE *** NBC News confirms that Ensign will announce his retirement from the Senate this afternoon. He will finish out the rest of his term but will not seek re-election, said a GOP source with knowledge of the decision.

Capitol Hill newspaper Roll Call reports that the scandal-encumbered Ensign is expected to announce his retirement. A spokeswoman for the senator told NBC News, "I have no further details to release at this time."

Retirement seems like a good bet: Ensign is up for re-election next year, and he's viewed as the GOP's most vulnerable Senate incumbent.

Why? His political standing tanked after it was revealed he had an affair with a staffer whose husband was a top Ensign aide. The husband alleged that Ensign promised to set him up as a lobbyist after he confronted the senator about the affair. Moreover, it also was revealed that Ensign's parents made a $96,000 payment to the couple.

Democrats and Republicans have been eyeing Ensign's seat before today's news. One Republican to watch is Rep. Dean Heller. A Democrat to watch is Rep. Shelley Berkley.

From NBC's Ken Strickland
With a new short-term agreement in place that gives lawmakers just 16 days before the government runs out of money, Senate Democrats are calling in their big gun: Vice President Joe Biden.

"In the next 24 hours, there will be some meetings that will be directed by Vice President Biden," Senate Majority Leader Harry Reid announced in a news conference today. "And I'm happy that, in fact, is the case."

Lawmakers postponed the threat of a government shutdown Wednesday, when the Senate passed a two-week spending bill that funds government operations through March 18th. But Democrats and Republicans are still sparring over spending cuts in a longer-term bill to keep the government running through the rest of the year.

Reid has refused to allow a vote on a House-passed measure that includes $61 billion in cuts, labeling the spending reductions proposed by House Republicans as “extreme.”

To bridge that chasm between the two sides, Democrats are calling in an old hand.

Biden has been no stranger to the Hill, even since leaving it to join the administration. A former senator who has personal relationships with key Senate Republicans, Biden played a critical role last year brokering a deal with Republican Leader Mitch McConnell on an extension of the Bush-era tax cuts.

While the White House has largely remained on the sidelines during Congressional budget negotiations, Democrats feel Biden's presence will present a united front. Democratic leaders say they’re being careful to ensure their proposed spending cuts don't conflict with the administration’s priorities.

"We want to be at one with the White House,” said Sen. Chuck Schumer, D-N.Y. “We want to be working together with them. We don't want to have them have a budget and we have a budget."

Republican leaders contend that Biden's role won't dramatically impact the talks, instead placing the onus on Senate Democrats to propose significant spending cuts.

Speaking to reporters on Wednesday, House Speaker John Boehner would not commit to taking part in negotiations with Biden, noting that talks between the two parties have already been in progress.

"I think it's important to make clear that we've been in discussions with our Democrat colleagues for weeks. This isn't something new," said Boehner. "And the House's position is, we passed a bill. It's out there. And I think it's time for [Democrats] to outline for us what's their position to keep the government funded."

Msnbc.com's Carrie Dann contributed

From NBC's Ken Strickland and Domenico Montanaro
Former President George W. Bush made a rare appearance in Washington, DC, today.

He spoke at a ceremony on behalf of his friend, and former Senate Majority Leader, Bill Frist on Capitol Hill.

"It takes a really good friend to get me to come back to Washington," Bush said.

From NBC's Ken Strickland
At a news conference today, Majority Leader Harry Reid said he expects the Senate to pass the House GOP's short-term spending bill within the next 48 hours, thereby averting a government shutdown.

The House is expected to pass the bill later today. It funds government operations for two weeks, containing $4-billion in spending cuts.

Prior to Reid's statement, Republican Leader Mitch McConell said he was "confident" the House bill would pass when it reached the Senate.

Reid said he and Senate Democrats wanted a bill longer than two weeks, allowing more time to negotiate a long term spending bill.  But Republicans rejected his proposals, Reid said.

From NBC's Ken Strickland
A statement released late Friday by the office of Senate Majority Leader Harry Reid suggests Congress is moving towards a deal to avoid a government shutdown--at least for the short term.  Democrats say they are "encouraged" by reports about the short term spending bill that House Republicans are expected to pass and send to the Senate on Tuesday.

"The plan Republicans are floating today sounds like a modified version of what Democrats were talking about." said Reid's spokesman Jon Summers in a statement.

A senior Democratic aide warned that the devil was in the details, and that leaders had yet to examine the full details of the entire House bill, which would fund the government for two weeks and includes $4-billion in spending cuts.

Still, Democrats appear to be much more optimistic about the short term fix than they had been earlier this week.

What's changed?

Yesterday, Senate Democrats said they were combing through the president's 2012 budget request, looking for spending cuts that could be applied this year. They also said they'd entertain cutting $8.5-billion worth of earmarks in the current spending bill that was passed by Congress in December.

Today, as House Republicans announced some of the details of their short term bill, they also cited earmarks and included similar cuts from the president's 2012 budget. (You can read the House proposal here.)

In a written statement, Senate Republican Leader Mitch McConnell said the House bill "focuses on bipartisan ideas to reduce federal spending."

"President Obama and congressional Democrats agree with Republicans that these are potential areas to reduce spending, removing any excuses they have offered for demanding their status quo spending levels,” McConnell wrote. “As a result, there is now a clear path to finishing this short-term measure before the March 4th deadline."

Privately, Senate Republicans feel they have boxed Reid into a procedural corner and forced him to accept the House-backed bill. GOP aides say it would have been almost impossible for Reid to pass a Democratic bill before the government runs out of money at the end of next week.

 If an agreement can be reached for a short term fix, a much larger fight remains on a longer-term bill that would fund government operations through September.

The long term bill that House Republicans passed last week contained $60-billion in spending cuts. Senate Democrats called it dead on arrival.

"We should keep our focus on what we need to do to cut spending and keep our economy growing in the long-term," said Reid's spokesman Jon Summers."But the 'my way or the highway' approach Republicans have been taking in the past only signals a desire for a government shutdown that our country can't afford. We hope this is a sign that they have abandoned it and will work with Democrats moving forward."

While Republicans say they “welcome” the news that Democrats appear fairly warm to their two-week spending proposal, GOP House leader Eric Cantor reiterated his party’s demand for deeper slashes to the longer-term measure that would fund the government until the end of the fiscal year.

“I’d caution my Senate Democrat colleagues to make sure that their cuts are significant and serious spending reduction proposals, not just minor efforts to trim around the edges,” he said in a statement.

Msnbc.com's Carrie Dann contributed.

From NBC's Ken Strickland
While maintaining their stance that any short-term agreement to avert a government shutdown should freeze spending at current levels, Senate Democratic staffers are starting to identify areas to cut spending for the long term in a bill that would fund government operations through this fiscal year.

According to a Democratic source, appropriations and leadership staff are going through President Obama's 2012 budget request to see which of those spending cuts could be applied this year. They're also considering cutting $8.5 billion worth of earmarks, which are included in the current funding bill that passed last December.

The source says Republicans are "trying to confuse people" by suggesting Democrats object to any spending cuts. 

Senate Democrats maintain that keeping spending at the current level provides billions of dollars in cuts when measured against president 2011 budget request. (However, that request was never enacted.)

"Senate Democrats have already agreed to a five-year spending freeze and $41 billion in spending cuts and we're willing to go further," said the Senate's No. 2 Democrat, Dick Durbin, in a written statement today. "But that requires the sort of good-faith negotiations House Republicans refuse to engage in."

From NBC's Jim Miklaszewski and Ken Strickland
Gen. David Petraeus has ordered an investigation into the Rolling Stone report alleging that Lt. Gen. William Caldwell improperly used "Psychological Operations" forces to target visiting dignitaries, including Sens. John McCain, Carl Levin, and even Joint Chiefs Chairman, Adm. Mike Mullen.

Meanwhile, Levin -- chairman of the Senate Armed Services Committee -- issued this statement:

For years, I have strongly and repeatedly advocated for building up Afghan military capability because I believe only the Afghans can truly secure their nation's future. I have never needed any convincing on this point. Quite the opposite, my efforts have been aimed at convincing others of the need for larger, more capable Afghan security forces, and that we and NATO should send more trainers to Afghanistan, rather than more combat troops. I am confident that the chain of command will review any allegation that information operations have been improperly used in Afghanistan.

From NBC's Mark Murray and Ken Strickland
New Mexico Sen. Jeff Bingaman (D) will not run for re-election in 2012, according to two sources with knowledge of his decision.

Bingaman was first elected in 1982, and he's currently serving his fifth term in the U.S. Senate.

Democrats say they're confident they will keep the Senate seat, especially in a presidential year (Obama won New Mexico with 57% of the vote in 2008). A top Dem candidate to replace Bingaman would be two-term Congressman Martin Heinrich (D).

Bingaman joins a 2012 Senate retiree list that includes Kay Bailey Hutchison (R-TX), Kent Conrad (D-ND), Joe Lieberman (I-CT), Jim Webb (D-VA), and Jon Kyl (R-AZ).

From NBC's Ken Strickland
Two Democratic senators are asking baseball commissioner Bud Selig to ban all tobacco use in the sport, specifically citing smokeless products.

Sens. Dick Durbin of Illinois and Frank Lautenberg of New Jersey are suggesting that Selig push for a ban as part of the negotiations in the players' collective bargaining agreement later this year.

Major League Baseball banned tobacco use in its minor leagues in 1993, but still allows it in the big leagues. The senators say Major League Baseball "is undoubtedly complicit" in the increase its use with school-aged boys.

In a letter to Selig, Durbin and Lautenberg wrote, "We now know conclusively that smokeless tobacco endangers the health of baseball players who use it, but it also affects millions of young people who watch baseball."

"The use of smokeless tobacco by baseball players undermines the positive image of the sport and sends a dangerous message to young fans, who may be influenced by the players they look up to as role models," they wrote

The senators say they were motivated to write the letter because of an recent newspaper article written by Washington Nationals pitcher Steven Strasburg. The pitcher said his initial use chewing tobacco stemmed from a desire to emulate pro baseball players.

Referencing a National Youth Risk Behavior Survey, the senators say the use of smokeless tobacco products has increased 36% among high school boys since 2003, raising its use among all boys to 15%.

"While tobacco companies spend millions on ads tailored to attract young people to use tobacco products, MLB is undoubtedly complicit in attracting many young people to try smokeless tobacco after seeing their baseball heroes chew tobacco," they wrote.

The senators sent an identical letter to Baseball Players Association Executive Director Michael Weiner.