Virginia state Sen. Emmett W. Hanger Jr. ( R-Augusta) announced Monday that he and the House budget chief had worked out details for a Medicaid expansion plan. (Bob Brown/AP)

A key state Senate Republican and the House budget chief have worked out a plan to allow up to 400,000 uninsured Virginians to enroll in Medicaid.

Sen. Emmett W. Hanger Jr. (Augusta) has long backed expansion of the federal-state health insurance program for the poor — but with conditions that seemed hard to square with the plan backed by the House.

But on Monday, one day before the Senate will reconvene for a possible vote on Medicaid, Hanger said he and House Appropriations Chairman S. Chris Jones (R-Suffolk) had come to terms.

Hanger and Jones announced their meeting of the minds in separate letters to colleagues in their respective chambers, a development first reported by the Richmond Times-Dispatch.

“I wouldn’t characterize it as a deal so much as we have a set of amendments to lay on the House bill, which I’m hoping the Senate will find favorable,” Hanger said in an interview.

Senate Majority Leader Thomas K. “Tommy” Norment Jr. (R-James City), who has opposed expansion, declined to comment through a spokesman.

The compromise contains a tax on hospitals that Hanger had opposed in the original House plan. It would pay for the state’s 10 percent share of the $2 billion-a-year cost of enrolling more Virginians in Medicaid.

In fact, the compromise includes a second hospital tax — one that the hospitals want because it would boost their bottom line: The tax would go right back to the hospitals and allow them to draw down more federal money in the form of higher reimbursement rates.

Hanger, who had objected to the way the original plan called for spending a projected financial windfall from Medicaid on teachers’ raises and other things unrelated to health care, said the new plan would devote more money to mental health care, substance abuse treatment and the state’s revenue reserves. Raises for teachers and other state employees are still in there, but are now contingent on the state meeting certain revenue projections.

Although they are both controlled by the GOP, Virginia’s House and Senate have disagreed about whether to expand Medicaid, with the House in favor and the Senate opposed. The impasse prevented the legislature from passing a state budget bill before adjourning its regular 60-day session in March.

The General Assembly needs to approve a budget measure by July 1 or face a government shutdown. The legislature reconvened last month for a special budget session, but the Senate has not put forth a plan even though senators have been called back to Richmond to vote on one Tuesday.

Senate Minority Leader Richard L. “Dick” Saslaw (D-Fairfax) said last week that he will resort to a “nuclear” procedural move — one that would yank the state budget bill away from the Senate Finance Committee — if the panel does not send a spending plan to the full Senate before it reconvenes at 3:30 p.m.

Saslaw said he will make a motion to “discharge” the committee, propelling the House’s budget bill to the floor against the panel’s wishes.

Hanger and another Republican, Sen. Frank W. Wagner (Virginia Beach), have indicated that they would support expansion under certain conditions — enough to pass a budget in the closely divided chamber.

Under the Affordable Care Act, championed by President Barack Obama, Washington allowed states to open their Medicaid rolls to people making up to 138 percent of the federal poverty level, which is $16,643 for an individual. The federal government has pledged to pay at least 90 percent of the cost, which in Virginia would amount to about $2 billion a year.

Thirty-one states, including Maryland, and the District of Columbia accepted the offer. But Virginia, which has one of the nation’s most frugal Medicaid programs, refused. Republicans said they feared that the federal government would withdraw its support and leave the state picking up the cost.