WASHINGTON — Independents who swept Barack Obama to a historic 2008 victory broke big for Republicans on Tuesday as the GOP wrested political control from Democrats in Virginia and New Jersey, a troubling sign for the president and his party heading into an important midterm election year.

Conservative Republican Bob McDonnell’s victory in the Virginia governor’s race over Democrat R. Creigh Deeds and moderate Republican Chris Christie’s ouster of unpopular New Jersey Gov. Jon Corzine was a double-barreled triumph for a party looking to rebuild after being booted from power in national elections in 2006 and 2008.