By Catalina Camia, USA TODAY
Democrats are calling Paul Ryan an "extremist" for his proposals to revamp Medicare.
Here is a sampling of reaction that is coming in on Mitt Romney's vice presidential pick:
From Jim Messina, President Obama's campaign manager:
In naming Congressman Paul Ryan, Mitt Romney has chosen a leader of the House Republicans who shares his commitment to the flawed theory that new budget-busting tax cuts for the wealthy, while placing greater burdens on the middle class and seniors, will somehow deliver a stronger economy.
The architect of the radical Republican House budget, Ryan, like Romney, proposed an additional $250,000 tax cut for millionaires, and deep cuts in education from Head Start to college aid. His plan also would end Medicare as we know it by turning it into a voucher system, shifting thousands of dollars in health care costs to seniors.
As a member of Congress, Ryan rubber-stamped the reckless Bush economic policies that exploded our deficit and crashed our economy. Now the Romney-Ryan ticket would take us back by repeating the same, catastrophic mistakes.
"Congressman Paul Ryan and Mitt Romney are a match made in millionaires' heaven, but they'll be a nightmare for seniors who've earned their Medicare benefits. For the last 18 months, we've said Republicans will have to defend the indefensible - their vote to end Medicare.
Rep. Steve Israel of New York, chairman of the Democratic Congressional Campaign Committee, said this:
"Now with Congressman Ryan on the ticket, House Republicans face the one thing they hoped to avoid - a national debate on their budget that puts millionaires first and Medicare and the middle class last."
American Bridge 21st Century, a Democratic super PAC, has set up a website with opposition research on Ryan, www.meetpaulryan.com.
"In every race across the country, the Ryan budget plan is the albatross that hangs around the neck of Republican candidates," the website says. "... There's nothing defensible about a budget that hands out tax cuts to wealthy individuals and corporations while asking more of working class families already struggling just to get by - and still doesn't even close the budget deficit until 2040."
From Adam Green, co-founder, Progressive Change Campaign Committee:
"Paul Ryan is a right-wing extremist who wants to end Medicare. 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. If Democrats win in a landslide, this was the game changer."