Majority Leader Harry Reid will have his work cut out for him next week balancing the competing demands of his caucus against a March 4 deadline to avert a government shutdown. 

The coming fight over the controversial House-passed spending bill will test the Nevada Democrat’s hold on his smaller 53-47 majority as well as the gentlemen’s agreement he struck with Minority Leader Mitch McConnell (R-Ky.) on allowing a more open amendment process than in the contentious 111th Congress.

Several moderate Senate Democrats told Roll Call they are considering supporting additional cuts beyond the domestic spending freeze that Reid and Senate Democratic leaders backed last week. The question isn’t whether those moderates would back the House Republican bill — Democrats appear united in opposition to that level of cuts as too extreme and dangerous with the economy still in the early stages of a recovery. Reid himself predicted no Democrat would back the House package as is. But Senate Republicans may be able to pick off enough Democrats to win votes on smaller packages of cuts as moderates look to burnish their fiscally conservative chops.

Reid has been preparing for the showdown for weeks, a Democratic leadership aide said. “He knew the work he would have ahead of him,” the aide said. “He started talking to his entire caucus early. … I think the caucus is actually more united than you might normally expect, and I think that’s in large part because there’s been a lot of work done on the front end.”

Democrats used their retreat in Virginia to coalesce on a message of supporting some cuts while painting the House GOP as extreme.

Indeed, several moderates have begun using a talking point that the CR cuts $41 billion to $44 billion from President Barack Obama’s budget, depending on whether Pell Grants are included. That is an apples-to-apples comparison to the $100 billion in cuts touted by the House GOP as meeting their “Pledge to America.”

“The Republicans factor that into their $100 billion, but for whatever reason it doesn’t seem to count when Democrats do,” the aide said. “Already we’re meeting them halfway.”

Republican aides wondered how open Reid will allow the amendment process to be given the potential for Democratic defections. They also wondered whether Reid might try to require a 60-vote threshold for germane amendments, which would allow him to suffer more defections while still keeping control of the bill. But doing so would violate at least the spirit of openness and freewheeling debate that has been the order of the day so far on both sides of the Capitol.

A Senate Republican aide said it will be interesting to see how Democrats message their CR if they can’t stick together on leadership’s plans to “keep spending the same amount of money as they are now.”

But Democratic leaders were mindful of the restlessness of some of their colleagues when they announced their support for a spending freeze as the opening bid in the coming negotiations with House Republicans last week.

There are “some members of our caucus who want to go farther, but at a minimum we are going to abide by this freeze,” Senate Democratic Conference Vice Chairman Charles Schumer (N.Y.) said.

With a 53-seat majority, it only takes four Democrats to join with Republicans to cut deeper. And several moderates say they would like to see deeper cuts.

“I think you have to start the process now in order to keep faith with the American public’s desires and to set the stage for more smart, targeted cuts in the ’12 budget,” Sen. Mark Udall said. The Colorado Democrat said, however, that the House GOP’s bill is too extreme.

“It seems like an orgy of cutting over there that really isn’t going to help our economy and job creation,” he said. “There is a strong sentiment in the caucus that we need to start this year. … But when you make the cuts quickly, without forethought, you have effects that are very damaging. Whether you are a surgeon or a leader here on Capitol Hill, you really want to plan this out.”

Sen. Ben Nelson likewise said he’d like to go beyond a spending freeze but wants to see what specific cuts are before signing on to anything.

“It’s a question of where and how much,” the Nebraska Democrat said. “It’s one thing to say you’d like cuts, it’s another thing to have a plan to do it.”

Sen. Jon Tester, however, said he supports the spending freeze and is worried about going much further in the near term.

“Remember, the freeze is still about $44 billion in cuts,” the Montana Democrat said, using Obama’s 2011 budget request as a benchmark. “I think we’ve got to be smart here. … To go at this willy-nilly and not be thinking about what we’re doing in the short term could really turn us upside down in a heartbeat. …. We need to make cuts, but they’ve got to be surgical and thoughtful.”

Sen. Mary Landrieu slammed not just the size of the Republican cuts in the House, but what she considers their indiscriminate cuts on successful and innovative education programs.

“Put me down, I’m for $41 billion in cuts and I may be even for more cuts, but I’m for eliminating waste, fraud, abuse, inefficiency, mediocre programs,” the Louisiana Democrat said. “I am not going to go quietly in the night eliminating the best programs in the country.”

One factor that appears to be helping Democrats unify is the rightward drift of the House bill, where a conservative revolt forced leaders to scramble to add $26 billion in cuts with more coming on the House floor. And a threat by Speaker John Boehner (R-Ohio) last week not to move any more short-term spending bills without additional cuts didn’t win him any friends among the Democratic rank and file either.

“Everybody understands that there need to be budget cuts, but what the House has done is too extreme,” Senate Budget Chairman Kent Conrad (D-N.D.) said. “There needs to be a negotiation.”