Sen. John McCain (R-Ariz.) endorsed Republican presidential candidate Mitt Romney Wednesday afternoon.
News of the endorsement broke Tuesday night ahead of the Iowa Caucuses, when a former aide to McCain told BuzzFeed that the 2008 Republican presidential candidate had plans to endorse Romney in the key early primary state of New Hampshire.
Romney flew in from Iowa in the morning after his narrow caucus win, and McCain joined him onstage – putting the Vietnam veteran back in front of audiences that handed him two primary victories here.
McCain, who is still hugely popular in the state, said his endorsement was intended to help Romney "get an overwhelming vote that will catapult this candidate to the White House."
Romney was governor of neighboring Massachusetts and holds a strong lead in polls in New Hampshire. With a precarious 8-vote win behind him, Romney is looking to voters here to hand him a victory that will make his eventual nomination seem all but inevitable.
Romney faces conservative challenges from former Pennsylvania Sen. Rick Santorum, who barely lost in Iowa, and former House Speaker Newt Gingrich, who has already started running newspaper ads declaring Romney too moderate.
McCain is particularly popular with the independents who can vote in the state's Republican primary. His endorsement could help Romney win over those voters and increase his overall support.
McCain and Romney haven't always been political allies. McCain beat Romney in the 2008 New Hampshire primary, and there is a history of acrimony between the two. But Romney eventually endorsed McCain in 2008.