Virginia Gov. Bob McDonnell (AP Photo/Steve Helber) (Steve Helber/AP)

One day after House and Senate negotiators struck a transportation funding deal, some Democrats were trying to link passage of that plan to the issue of Medicaid expansion.

Some House Democrats vowed to vote against the transportation package if the General Assembly does not lay the groundwork this year for expanding Medicaid. They are also threatening to vote against state budget amendments if they do not include a framework for expansion.

In a letter sent Thursday to the chairmen of the House Appropriations and Senate Finance committees, 24 Democratic delegates urged passage of the Senate’s version of the budget amendments, which is more open to Medicaid expansion than the House bill.

“Our economy cannot afford to lose out on $3 billion,” the letter to Del. Lacy E. Putney (I-Bedford) and Sen. Walter A. Stosch (R-Henrico) said. “And we simply cannot support a budget that doesn’t expand Medicaid.”

Del. Patrick A. Hope (D-Arlington), one of the signatories, said there also is a growing movement within the Democratic caucus to block the transportation funding package unless Medicaid is expanded. “That sentiment is growing,” Hope said.

But Republicans rejected any connection between the two.

“We did not want linkage between transportation and Medicaid. I’d be very disappointed to hear any group starting to make that linkage,” Sen. Majority Leader Thomas Norment (R-James City) said.

Democrats, who took a public-relations blow last session when they threatened to hold up the state budget in a bid for power-sharing in the evenly split Senate, did not appear to be united behind a strategy to link the two issues.

“There are some people who believe it’s an opportunity to get Medicaid expansion simultaneously by holding out on the transportation bill,” said Del. Onzlee Ware (D-Roanoke City). “I disagree with that. I honestly think [the transportation measure is] a reasonable compromise, and if we don’t do it this year, we won’t get it for years.”

But Del. Jennifer L. McClellan (D-Richmond), disagreed, tweeting on Thursday: “In my district, voters care more about Medicaid expansion and K-12 education than transportation funding.”

Neither the House nor Senate had voted on the transportation proposal by Thursday, although both chambers were still in session into the evening. Medicaid is the major sticking point in negotiations, budget conferees have said.

On Wednesday, House and Senate negotiations struck a deal on a transportation funding overhaul intended to address the state’s chronic shortage of road and transit funds. The deal would raise about $880 million a year through a complex mix of tax cuts and increases. It would cut the gas tax but allow it to rise with inflation; raise the sales tax and car titling tax; and divert existing revenue from the general fund to transportation.

Considered the most significant road-funding reform in nearly a generation, and the most important legislation of the session, it went nowhere on the floor Thursday — just two days before Saturday’s scheduled sine die.

Time was also running out for the General Assembly to complete work on a package of amendments to the current two-year budget, which began in July. Neither chamber included language in its budget bill to expand Medicaid, the health-care program for the poor, disabled and elderly. But the Senate version would set up a framework for expansion if Washington allows Virginia to make reforms to how the program is administered in the state.

Under the federal Affordable Care Act, states have the option to open their Medicaid programs to people with incomes up to 138 percent of the national poverty level — about $32,000 for a family of four — with the federal government paying the entire cost for the first three years. The federal share gradually declines to 90 percent.

Virginia would initially receive about $2 billion a year from Washington under the program. But some Republicans, including Gov. Robert F. McDonnell, have been skeptical that Washington will have the money to make good on that promise.

“The country is broke, and I will not support policies that make it worse,” McDonnell said in a letter to Stosch and Putney.

Errin Haines contributed to this report.