Coalescing scandals have engulfed Virginia’s leaders, plunging the state into political free fall.

First, Gov. Ralph Northam came under fire for a racist yearbook photo, which he acknowledged and then denied appearing in. He also admitted to wearing blackface to dress up as Michael Jackson in the 1980s.

Then Lt. Gov. Justin E. Fairfax was accused of sexual assault by two women, allegations he has strongly denied. And the state’s third-ranking elected official in Virginia, Attorney General Mark R. Herring, has acknowledged that he, too, wore blackface as a younger man.

Only a week ago, it seemed that Mr. Fairfax, who is African-American, was poised to ascend to the governorship and lead Virginia through a reckoning with its painful history on race. But now he is facing the threat of impeachment proceedings, while the state’s other two top leaders, both white, are resisting calls to quit over past racist conduct.

Here is what the law says about removing Virginia politicians from office, why Mr. Fairfax’s case could throw gasoline on this political fire and what could happen next if Mr. Fairfax were to be forced out of office.

“Things look rather dim for him,” said Larry J. Sabato, the director of the Center for Politics at the University of Virginia. But he cautioned against speculation in the midst of a political storm.

“Remember,” he said, “a week ago, we thought the lights were out for Northam.”

There is no clear succession plan should Mr. Fairfax leave office, and because of conflicting laws and interpretations, a political fight could explode over how to replace him.

The Virginia Constitution says that when there is no explicit provision for how to fill a vacancy, the governor appoints a replacement to serve until the next regularly scheduled election. “It’s the catchall clause,” said Dr. Dinan.

Separately, a Virginia law says that if the lieutenant governor’s office is vacant, the president pro tempore of the State Senate would “discharge the duties of the office,” Dr. Dinan said. But the Constitution makes a point to say that is not the same thing as filling a vacancy, he said. The president pro tempore “is just discharging the duties temporarily,” he said.

In 1982, the attorney general’s office weighed in on the conflict in a ruling that said “the governor has the discretionary power to fill a vacancy in the office of lieutenant governor.”

Senior Virginia Democrats are making the case that Mr. Northam should appoint State Senator Jennifer McClellan to replace Mr. Fairfax. Ms. McClellan, who is black, is a longtime Richmond legislator who has a close relationship with United States Senator Tim Kaine.

But political opponents of Mr. Northam are likely to balk at allowing him to choose the next lieutenant governor, at a time when he is under a cloud of mistrust.