Romney chooses Ryan as VP pick

Updated 7:43 a.m. ET

(CBS News) It's official: Mitt Romney's campaign has announced he has chosen Wisconsin Rep. Paul Ryan to be his running mate, bringing to the ticket a youthful budget hawk who will help underscore the GOP ticket's focus on righting the economy with substantial changes to government spending.

The Romney campaign communicated the pick via iPhone app at around 7 a.m. Saturday. Ryan will join Romney for an appearance in Norfolk, Va., on the deck of the USS Wisconsin at 9 a.m.

Ryan, 42, is a bold - and risky - choice. The chairman of the House Budget Committee, has proposed fundamental changes to the social safety net, including eventually turning Medicare into a system of direct payments to seniors that would allow them to buy their own insurance. Ryan has also called for replacing Medicaid with lump sum payments to states, who can use them as they see fit, and sought to allow workers to invest a portion of their payroll taxes, which fund Social Security, in private accounts. (Some of these proposals have been tweaked or abandoned.)

Democrats have used Ryan's proposals to criticize the vast majority of Republicans who voted in favor of his budget plan, which Romney has embraced. While many conservative opinion writers have rallied around Ryan, saying his proposals represent a necessary effort to reign in the debt and deficit, some have suggested his positions could sink the GOP. When Ryan released his budget plan, conservative columnist Charles Krauthammer wrote that "at 37 footnotes, it might be the most annotated suicide note in history." And then-presidential candidate Newt Gingrich famously referred to Ryan's Medicare plan as "right-wing social engineering", which resulted in criticism from Gingrich's fellow Republicans.

Ryan, a Janesville native who has represented Wisconsin's 1st district since 1999, is a likeable and natural presence on the campaign trail. He has been a strong advocate for Romney and could help Republicans win his home state, which President Obama won comfortably in 2008, but which is very much up for grabs this year. The state has seen a number of dramatic political developments in the past two years, with conservative Republican Gov. Scott Walker surviving a recall election this year. A strong debater who appears prepared to face off with Vice President Joe Biden, he will energize a conservative base that has shown skepticism about Romney due to his record as Massachusetts governor.

Romney's selection of Ryan represents a fundamental change in campaign strategy. The presumptive Republican presidential nominee has until this point sought to make the election largely a referendum on the president. That ends with the choice of Ryan, a policy wonk who has offered up a clear and detailed alternative to the president's policies. His addition to the ticket will likely move the political conversation in a more substantive direction, with the two sides are offering clear alternatives to the American people.

A former Hill staffer, Ryan has spent most of his professional life in Washington - he won his seat when he was just 28 - and he could undercut Romney's message that America needs a tested political outsider at the helm of the economy. He has gone toe-to-toe with the president in public forums, and argues that the president wants to move the United States toward a "European" style of government. His policies have been celebrated by conservative think tanks and opinion leaders, who see Ryan as a potentially transformative figure who can convince Americans that the time has come to reign in entitlement programs as part of what Ryan calls the "Path To Prosperity." http://paulryan.house.gov/uploadedfiles/pathtoprosperity2013.pdf

The president has called Ryan's proposals "deeply pessimistic."

"There's nothing serious about a plan that claims to reduce the deficit by spending trillions of dollars on tax cuts for millionaires and billionaires," he said last April. "And I don't think there's anything courageous about asking for sacrifice from those who can least afford it and don't have any clout on Capitol Hill."