WASHINGTON — Immigration may have cost Majority Leader Eric Cantor his election. His defeat almost certainly dooms the issue in the House.

Cantor, R-Va., was supposed to cruise to victory in Tuesday’s GOP primary over Dave Brat, an underfunded political novice who is an economics professor at Randolph-Macon College.

The only question was how wide Cantor’s winning margin would be. Immigration advocates were watching intently, hoping that if it was big enough, Cantor would feel free to green-light action on immigration legislation in the House.

Instead Cantor lost, decisively, after a campaign in which Brat made immigration the central issue. Brat accused Cantor of embracing “amnesty” and open borders, signed an anti-immigration pledge, and got assists in recent weeks from conservative figures popular with tea party voters such as radio host Laura Ingraham and columnist Ann Coulter, who labeled Cantor “amnesty-addled.”

Cantor fought back, boasting in strongly worded mailers of shutting down plans to grant “amnesty” to “illegal aliens” — a changed tone for a lawmaker who’d spoken out in favor of citizenship for immigrants brought illegally to this country as youths.