Mr. Youngkin’s attacks have forced Terry McAuliffe, the Democratic former governor trying to win back his old job, onto the defensive, and have thrust the ordinarily local issues surrounding schools into the middle of a rancorous nationwide shouting match.

The Virginia race offers an early electoral test of that conservative energy.

A victory by Mr. Youngkin would mark the first statewide win for Republicans in a dozen years and likely trigger a political panic within the Democratic Party about its prospects in next year’s midterm elections. Some Republican officials and strategists liken the surge of activism to the Tea Party, the anti-government movement that helped them win control of the House in 2010 and unleashed a revival of outrage politics that would define their party for the next decade.

“There’s just so much focus on the schools, and it’s visceral,” said John Whitbeck, a former chairman of the Republican Party of Virginia from Loudoun County, where acrimonious school board meetings have led to arrests, death threats and constant airtime on conservative media. “It’s not like, ‘Oh, I’m against the debt ceiling.’ This is like, ‘You’re destroying our children’s education.’ And, look, angry people vote.”