COLUMBUS, Ohio — Mitt Romney chalked up Super Tuesday victories in Virginia, Vermont and Massachusetts, extending his winning streak as he sought to fasten his grip on the GOP nomination.

Former House Speaker Newt Gingrich won Georgia, the state he represented for years in Congress and where he retreated for a last stand to resurrect his sagging campaign.

“Thank you Georgia!” Gingrich tweeted soon after the television networks projected his victory. “It is gratifying to win my home state so decisively to launch our March Momentum.”

All four states were performing as expected, rewarding candidates in their home regions and, in the case of Virginia, where former Massachusetts Gov. Romney faced no serious opposition. In all, voters in 10 states were casting ballots in Super Tuesday contests that promised to either push Romney beyond the reach of rivals, or stoke Rick Santorum’s challenge and reopen the question why Republican voters won’t embrace the party’s national front-runner.

The most crucial test was in Ohio, a November battleground, where Romney and the former Pennsylvania senator devoted the bulk of their time and resources. Both candidates focused on the economy in a Rust Belt state that hurt long before the rest of the country sunk into deep recession, then emerged to a fitful recovery.

Santorum touted his roots across the border in a Pennsylvania steel town, saying he would seek to strengthen the economy by restoring America’s manufacturing might. Romney unveiled a new slogan — “more jobs, less debt, smaller government” — and jabbed at Santorum’s digression into subjects such as contraception and the separation of church and state.

“During this campaign there has been discussion about all sorts of issues,” Romney said in Canton, Ohio. “I keep bringing it back to more jobs, less debt and smaller government. That’s what my campaign is about.”