The budget proposes sweeping changes to the popular government-run Medicare healthcare program for the elderly, a politically risky gambit for Republicans who faced a voter backlash last year when they offered a similar plan.

It also seeks to cap discretionary federal spending on education, transportation and other government programs at $1.029 trillion, roughly $18 billion less than Democrats want. That sets up a battle over spending that, if unresolved, could lead to a government shutdown later this year.

While its proposals have little chance of becoming law due to opposition in the Democratic-controlled Senate, Republicans in the House of Representatives are looking for the plan from Congressman Paul Ryan to provide a lift to their re-election fortunes in November.

After a string of debacles ranging from last summer's debt-limit standoff to a near-revolt over extending a payroll tax cut, Republicans want to get back to their core message of shrinking the size of government. They claim an advantage over Obama on spending, debt and taxation and intend to use Ryan's budget plan to exploit it.

Where Obama wants to raise taxes on the wealthy and boost near-term spending on infrastructure and education, the Republicans want to cut taxes and spending on healthcare and social safety net programs - benefits used more by the poor and middle classes.

The Republican budget plan would produce deficits totaling $3.13 trillion in the next 10 years - less than half the $6.39 trillion in deficits the Congressional Budget Office says Obama's fiscal 2013 budget plan would rack up.

The Republican plan claims to put U.S. debt on a downward path, to 62.3 percent of U.S. economic output by 2022, versus Obama's 76.3 percent, which is slightly above current levels.

Ryan said in the document that U.S. debt growth, if left unchecked, would spark a debilitating European-style debt crisis.

"The growing possibility of such a crisis is creating debilitating uncertainty about the future, hurting job creation and economic growth today," he wrote.

DISMANTLING HEALTHCARE REFORM

The Republican budget achieves much of its deficit-reduction goals through savings gained by dismantling Obama's 2010 healthcare reform law and by turning social safety net programs like food stamps and the Medicaid program for the poor into block grants for states.

After proposing last year to convert Medicare into a voucher-like program to allow seniors to purchase private health insurance, Ryan has modified his reforms in a bid to blunt criticism that it would shift too many costs onto the elderly.