Mr. Romney made the announcement aboard the USS Wisconsin later in the day, and the campaign has dubbed the ticket “America’s comeback team.”
Mr. Ryan, is slated for formal nomination by delegates to the Republican National Convention in Tampa, Fla., at the end of this month.
Mr. Ryan, 42, is the House Budget Committee chairman and a favorite among many in his party, especially economic conservatives because he has made budgetary reform and spending restraint the hallmark of his political career in Washington.
He proposed a budget plan that won wide acclaim among conservatives.
The Ryan pick is expected to assuage fears among his party’s conservative wing that he would repeat the expansion of government and the excessive spending of the last two Republican presidents.
A pro-life Catholic, Mr. Ryan as much as any Republican in office is trusted on fiscal as well as social matters.
“I can tell from our survey of our members that Ryan, along with [Florida Sen. Marco] Rubio, was one of the top picks for vice president,” said Ralph King, state coordinator of the Ohio Tea Party Patriots, which has more than 100 tea party chapters statewide.
“I guess the grass roots will be more energized than if they had picked [Ohio Sen. Rob] Portman or some of the others they talked about,” Mr. King said.
Though they like him generally, some conservative activists think Mr. Ryan’s budget proposal didn’t go far enough fast enough.
“I appreciate Ryan’s strong stand against Obamacare and how he did stand up to the president,” said Jason W. Hoyt, an activist with the Central Florida Tea Party. “But I’m very disappointed with the Ryan budget plan because it would not balance the budget ‘til the year 2040. So, yes, in that sense, Ryan is not as conservative as I wish he was.”
Liberals, meanwhile, plan to use that budget against the ticket, saying it would hurt seniors on Medicare and make other deep cuts to the social safety net.
“Paul Ryan is a right-wing extremist who wants to end Medicare,” said Adam Green, co-founder of the Progressive Change Campaign Committee. “This is a major unforced error by Mitt Romney. It gives President Obama and Democrats a chance to draw a clear contrast in 2012 by promising not to cut one penny from Medicare or Social Security benefits.”