RICHMOND — Virginia Gov. Terry McAuliffe is considering expanding health coverage for the poor without the approval of the state legislature, a move that would muscle his top priority past Republican opponents but also throw his young administration into a partisan firestorm and uncertain legal territory.

McAuliffe, a Democrat, and his top advisers have consulted lawyers, health-care experts and legislators on how to bypass the GOP-dominated House of Delegates, according to three people familiar with the discussions. A fourth, who like the others spoke on the condition of anonymity because they were not authorized to reveal private strategy, said the office of Attorney General Mark Herring, a Democrat, has been researching the matter.

The move would allow Virginia to take advantage of a key state option under the Affordable Care Act, and it could help break a budget stalemate and avert a looming government shutdown. But it would be a daring action; only two other governors have done anything similar to bulldoze Medicaid expansion past opponents.

If McAuliffe follows through, he would raise far-reaching constitutional questions about the chief executive's power and the rule of law — issues cropping up with increasing frequency in the states and in Washington, as governors and President Barack Obama seek to push past adversarial legislatures and Congress.

The action would also surely create a politically toxic environment for McAuliffe, a new governor who just passed the 100-day mark of his term, and it could launch legal challenges that he is by no means assured of defeating.

"I don't believe that he has that authority," said state Del. S. Chris Jones, R-Suffolk, chairman of the House Appropriations Committee and a central adversary in the budget stalemate with McAuliffe.

Even nonpartisan observers were uncertain of McAuliffe's position. "I don't know what the legal theory would be, frankly," said A.E. Dick Howard, a University of Virginia legal scholar who was chief draftsman of the state constitution when it was revamped in 1971.

McAuliffe and Herring sidestepped questions this week about the possibility of expanding Medicaid by executive action. Their spokesmen declined to comment Thursday.

Just two governors, in Ohio and Kentucky, have relied on their executive authority to buck reluctant legislatures to expand Medicaid under the Affordable Care Act, according to health-policy experts. And their examples do not provide a clear path for McAuliffe because those governors took advantage of legal quirks in those states.

Republican Gov. John Kasich of Ohio was able to tap an administrative board that normally oversees state contracting to approve expansion. In Kentucky, Gov. Steve Beshear, a Democrat, could authorize expansion unilaterally because Medicaid eligibility rules are set in state regulations, which can be changed by executive order, rather than state code, which is set by the legislature.

Going the expansion-by-executive-action route might be more difficult in Virginia, where the state constitution requires the legislature to approve all appropriations — even pass-through funding from Washington, which has promised to foot the full bill for Medicaid expansion for the first three years.

For months, while still pushing for expansion through the General Assembly, McAuliffe advisers have been searching for a solution even if the state House won't go along, the three people familiar with those discussions said. They've picked the brains of health-care advocates and assured expansion-minded legislators that they are "exploring their options," as one person familiar with those discussions put it.

State Sen. Emmett Hanger Jr. of Augusta County, one of three Senate Republicans who support expansion, said the possibility has come up many times in meetings between legislators and administration officials. Hanger stopped short of saying that the administration is pursuing that strategy; he said no one has ever told him.

"They're intrigued by what Governor Kasich did in Ohio," Hanger said. "There have been numerous instances where the speculation turned to whether or not it could be done administratively, but there's never been anyone that has clearly said, 'Yes and we're working on a plan.' "

Officials have always said in such meetings that McAuliffe's legal authority to make such a move was a "gray area," said Hanger. In any case, Hanger thinks such a move would stir up too much ill will and might not stand up to a legal challenge.

"Whether they can or can't, that's not where I want to be," Hanger said. "I think it would be an bold step that would lead to a lot of controversy and lawsuits because it would not be clear [legally]. But on the other hand, if a governor felt that strongly about it and just proposed to do it, I suppose the only way to stop him would be a lawsuit. But it would be quick in coming."

McAuliffe's more partisan supporters, meanwhile, said they would stand behind him. "If the governor concludes he has that ability, I support him 1,000 percent," said state Sen. A. Donald McEachin, D-Henrico.

State House Republicans have grown increasingly vocal about the possibility, particularly after Herring bucked the General Assembly's wishes this week by declaring that some young illegal immigrants are eligible for in-state tuition. Three months earlier, Herring had announced that the state's ban on gay marriage — something the legislature still supports — is unconstitutional.

McAuliffe's comments in recent days have only strengthened the perception that there was an executive plan in the works. Asked on a radio program whether he was pursuing a way to sidestep the General Assembly to make expansion happen, McAuliffe said: "Everybody says that. I'd like them to tell me and all my lawyers exactly how we do that. . . . I ran saying I want to work in a bipartisan way. I want to get this done legislatively."

Mark Lewis, co-host of WTOP's "Ask the Governor" program, pressed him. "So you don't have the authority to make this happen?"