Boston ? Republican campaign dropout Mitt Romney endorsed John McCain for the party’s presidential nomination and asked his national convention delegates to swing behind the likely nominee.

“Even when the contest was close and our disagreements were debated, the caliber of the man was apparent,” the former Massachusetts governor said, standing alongside his one-time rival at his now-defunct campaign’s headquarters. “This is a man capable of leading our country at a dangerous hour.”

“Primaries are tough,” said McCain, referring to their earlier rancor. “We know it was a hard campaign and now we move forward, we move forward together for the good of our party and the nation.”

The two met privately before appearing together at a news conference.

McCain effectively sealed the nomination last week when Romney withdrew from the race; only former Arkansas Gov. Mike Huckabee and libertarian-leaning Texas Rep. Ron Paul remain. But neither has a chance to catch McCain in the convention delegate hunt.

In early primaries and caucuses, Romney collected 280 delegates. The number is enough to move McCain close to the total of 1,191 needed to clinch the nomination a full nine months before the November general election.

Officials said the former Massachusetts governor made his decision to back McCain earlier in the day, citing a desire to help the Arizona senator wrap up the nomination before too much more time passed and while Democrats still did not have a nominee.