RICHMOND -- The honeymoon is over for Democrats in the Virginia Senate.

Partisan squabbling broke out Monday in the usually collegial Senate over its proposed budget bill, which largely parallels the version proposed by Gov. Tim Kaine.

Although Senate Democrats hold a slim majority and should be able to pass their version of the budget, a less-than-unanimous vote could weaken their hand heading into negotiations with the Republican-controlled House of Delegates.

The Democrats won their Senate majority after November's elections that broke a decade of Republican control.

Senate Republicans said Monday that the Democrats' proposed budget places a lower priority on pre-existing, core government services than it does on new programs proposed by Kaine that would expand pre-kindergarten eligibility and provide premium subsidies to uninsured Virginians. They also take issue with its use of about $420 million from the state's "rainy day" reserve fund.

Senate Finance Committee Chairman Charles Colgan, D-Manassas, accused Republicans of playing politics with what is "our most important work."

"We're going down a road that worries me," Colgan said. "We've now decided to make this a political budget, a political vote."

Republicans denied they were politicizing the budget. Sen. William Wampler, R-Bristol, the ranking Republican on the finance committee, suggested the budget was based on unrealistic assumptions and funneled needed funds for schools, hospitals and nursing homes toward the governor's initiatives.

"It's all right to differ with the governor when the executive budget is introduced," Wampler said. "That is when the Senate has performed its best work."

Sen. Edd Houck, D-Spotsylvania County, fired back in defense of the pre-kindergarten expansion, a plan that Kaine made a major part of his successful Democratic campaign for governor.

"It takes a lot of guts to start kicking around -- politically -- poor, 4-year-old children. Man, that's leadership," Houck said sarcastically.

Senate Minority Leader Thomas Norment, R-Williamsburg, called that "demagoguery."

"Something is not political just because someone disagrees with you on policy issues," Norment said. "That doesn't immediately deteriorate it down to political rhetoric."

The floor speeches came one day after Republicans on the Senate Finance Committee voted "no" on the budget proposal, resulting in a 9-7 approval of legislation that frequently receives a unanimous committee vote.

Interparty fighting over budget specifics is standard for the House of Delegates, but it's a surprising break from status quo in the Senate, where moderate members of both parties have long held sway.

"I'm really sorry that it has degenerated so quickly to this level," said Sen. Janet Howell, D-Fairfax County.

Norment said afterward, however, that as a lawyer used to rhetoric, "This is just business to me."

The House budget plan won unanimous approval from its Appropriations Committee on Sunday. The committee's chairman, Del. Lacey Putney, I-Bedford, told the full House on Monday that the spending plan represents "a pragmatic and responsible approach to meeting the core services of government in times of fiscal austerity, without increasing the burden on Virginians through higher taxes and fees."

But House Minority Leader Ward Armstrong, D-Henry County, charged that the emerging House plan would reduce new spending for basic aid to education by an estimated $100 million, thanks to changes the committee proposed in calculating the state's share of school funding costs.

Senate Republicans suggested that at least some of their opposition to the Senate version of the budget bill stems from discomfort with the process by which the budget was drawn. This is the first year since the retirement of longtime Finance Committee Chairman John Chichester, a Republican, and the first since Democrats held power since the mid-1990s.

Wampler said that under Chichester, "the Senate Finance Committee always tried to build a consensus on the most important matters" before a vote was taken. Norment and Wampler both said that consensus was absent this year.

"The threshold questions of getting into the rainy-day fund to pay for new programs, cutting school construction to expand the pre-K initiative -- we just didn't feel like we could do that," Wampler said.

Monday's acrimony may be the sign of things to come -- or it may have been just a moment for senators to vent their frustrations. They've got until the budget comes up for a floor vote on Thursday to patch things together and work for a compromise.

That likely will not be done in open session, but in offices, in hallways and on walks between buildings.

Even as Wampler finished an interview after the floor session, he flagged down Colgan as he passed by.

"Hey Chuck, walk with me," Wampler said to the finance committee chairman, and the two chatted as they strolled down a flight of stairs.

Staff writer Michael Sluss contributed to this story.