Updated 6:21 pm. - TAMPA, Fla. -- Republicans formally nominated Mitt Romney for president on Tuesday, minting the former Massachusetts governor as the party's official opponent this fall versus President Barack Obama.

Romney has been the presumptive Republican presidential nominee since late spring, when his major opponents ended their campaigns for president. But he will be able to shed the "presumptive" qualifier when he formally accepts the nomination during his Thursday night speech.

David Goldman / AP Wisconsin Gov. Scott Walker speaks as as Mitt Romney is nominated by the state delegates for the Office of the President of the United States at the Republican National Convention in Tampa, Fla., on Tuesday, Aug. 28, 2012.

Republicans held the roll call of state delegations late Tuesday afternoon, delayed from its initial scheduled vote during Monday's hurricane-canceled session. Convention Secretary Kim Reynolds presided over the vote.

"I am truly honored to annouce these votes for a man who happens to be my brother, and whom I love: Mitt Romney, the next president of the United States," said Scott Romney, the brother of Mitt Romney, in leading Michigan's delegation in casting its votes.

Shortly thereafter, Republicans nominated Wisconsin Rep. Paul Ryan as their vice presidential candidate by acclimation.

Slideshow: The 2012 Republican National Convention

There were occasional outburts of cheers for Texas Rep. Ron Paul when some states' delegates voted for the retiring congressman. Some delegates abstained from voting in instances, suggesting their dissenting opinion from Romney.

NBC's Chuck Todd has the latest from the Republican National Convention; plus, Andrea Mitchell, John Yang and Luke Russert visit Romney supporters in New Hampshire, Maine and West Virginia.

The fanfare on Romney's behalf at the convention hall made the delegate math of the Republican primaries earlier this year almost seem like an afterthought. Romney's battles with former House Speaker Newt Gingrich and former Pennsylvania Sen. Rick Santorum had seemed, for a time, to threaten to transform the battle for the GOP nomination into a protracted delegate battle.

When Romney accepts the nomination, he'll be able to access and spend tens of millions of dollars he has raised in general election funds. This formal distinction will enable the former Massachusetts governor's campaign to spend millions more on organization and television ads heading into the height of the fall campaign.