(AP) -- House Majority Leader Eric Cantor was defeated Tuesday by a little-known economics professor in Virginia's Republican primary, a stunning upset and major victory for the tea party.

Cantor is the second-most powerful member of the U.S. House and was seen by some as a possible successor to the House speaker.

His loss to Dave Brat, a political novice with little money marks a huge victory for the tea party movement, which supported Cantor just a few years ago.

Brat had been a thorn in Cantor's side on the campaign, casting the congressman as a Washington insider who isn't conservative enough. Last month, a feisty crowd of Brat supporters booed Cantor in front of his family at a local party convention.

His message apparently scored well with voters in the 7th District.

"There needs to be a change," said Joe Mullins, who voted in Chesterfield County Tuesday. The engineering company employee said he has friends who tried to arrange town hall meetings with Cantor, who declined their invitations.

Tiffs between the GOP's establishment and tea party factions have flared in Virginia since tea party favorite Ken Cuccinelli lost last year's gubernatorial race. Cantor supporters have met with stiff resistance in trying to wrest control of the state party away from tea party enthusiasts, including in the Cantor's home district.

Brat teaches at Randolph-Macon College, a small liberal arts school north of Richmond. He raised just more than $200,000 for his campaign, according to the most recent campaign finance reports.

Beltway-based groups also spent heavily in the race. The American Chemistry Council, whose members include many blue chip companies, spent more than $300,000 on TV ads promoting Cantor. It's the group's only independent expenditure so far this election year. Political arms of the American College of Radiology, the National Rifle Association and the National Association of Realtors also spent money on ads to promote Cantor.

Brat offset the cash disadvantage with endorsements from conservative activists like radio host Laura Ingraham, and with help from local tea party activists angry at Cantor.

Much of the campaign centered on immigration, where critics on both sides have recently taken aim at Cantor.

Brat has accused the House majority leader of being a top cheerleader for "amnesty" for immigrants in the U.S. illegally. Cantor has responded forcefully by boasting in mailers of blocking Senate plans "to give illegal aliens amnesty."

It was a change in tone for Cantor, who has repeatedly voiced support for giving citizenship to certain immigrants brought illegally to the country as children. Cantor and House GOP leaders have advocated a step-by-step approach rather than the comprehensive bill backed by the Senate. They've made no move to bring legislation to a vote and appear increasingly unlikely to act this year.

Cantor, a former state legislator, was elected to Congress in 2000. He became majority leader in 2011.