"If we don't tackle these debt problems soon, they're going to tackle us as a country."

Ryan was speaking on behalf of his budget resolution, which would cut more than $5 trillion more than President Obama's budget, reduce spending in 2013 and 2014 compared to 2012, and revive his proposal last year to turn Medicare into a health insurance supplement program for anyone younger than 55.

These changes drew criticism from Democrats who said Ryan's budget would hurt job creation at a fragile time, and hurt Americans who depend on government programs.

"It is a recipe for national stagnation and decline," Budget Committee Ranking Member Chris Van Hollen (D-Md.) said. "It retreats from our national goal of out-educating, out-building, out-competing the rest of the world."

Van Hollen and others also argued that the bill leans too heavily on spending cuts, and not enough on new tax revenue, and said the budget alternative he would be proposing includes these new revenues.

"Because our Republican colleagues refuse to ask millionaires to contribute one cent to deficit reduction, they hit everyone and everything else," Van Hollen said.

Rep. Tom McClintock (R-Calif.) recalled last year's similar debate over the Ryan budget plan, and excoriated Democrats for making personal attacks against Ryan but failing to find a better way forward to reduce the deficit.

"The Senate Majority Leader complained that it threatened the cowboy poetry festival in Elko, Nevada," McClintock said. "An allied group ran a smear campaign depicting Congressman Ryan as a monster, wiling to throw his grandmother off a cliff.

"Sadly, that's what passes for reasoned discourse from today's left."

The House planned a four-hour debate on the Ryan budget plan, and could take up as many as six alternative budget proposals tonight and Thursday.