In a much-anticipated speech, President Obama responded to the Republican deficit-reduction plan, vowing to cut $4 trillion over the next 12 years. The political stakes were huge. Obama was tasked with addressing the seriousness of the deficit, without cutting programs that would anger his Democratic base while providing an alternative to the plan put forth by Rep. Paul Ryan. He did this by drawing a line in the sand on the nation's social safety net and arguing for a roll back of the Bush-era tax cuts for the rich.

Obama's budget plan endorses many of the recommendations made by the Simpson-Bowles debt commission, including cutting defense spending and increasing the non-security spending freeze. And the president geared up for another fight on the Bush cut. After compromising this winter to extend the cuts another two years in exchange for unemployment benefits, Obama seems ready to argue during the 2012 campaign that it's time for the nation's most wealthy to pitch in. Returning the tax rates for those making over $250,000 to Clinton-era levels for would net the federal treasury $1 trillion.

The portion of the Republican plan that received the most attention, though, was Medicare and Medicaid. The proposal would phase out Medicare, turning it into a voucher program, and severely reduce the amount the federal government pays to the states for Medicaid. Obama promised to reform these programs, but refused to watch them fade away. Here's what he said:  

I will preserve these health care programs as a promise we make to each other in this society. I will not allow Medicare to become a voucher program that leaves seniors at the mercy of the insurance industry, with a shrinking benefit to pay for rising costs. I will not tell families with children who have disabilities that they have to fend for themselves. We will reform these programs, but we will not abandon the fundamental commitment this country has kept for generations.

There will be a lot more discussion in the hours and days to come about Obama's political balancing act, but the president appears to have won over at least one respected progressive writer. In his quick analysis of the proposal, Washington Post writer Ezra Klein wrote, "It goes a lot further than Ryan’s budget does in terms of actually figuring out ways to save money rather than just using caps to shift costs onto states/beneficiaries."

Still, some worry that as an opening salvo from the left, Obama's plan gives up too much ground. Nobel laureate and New York Times columnist Paul Krugman wrote, "I could live with this as an end result. If this becomes the left pole, and the center is halfway between this and Ryan, then no — better to pursue the zero option of just doing nothing and letting the Bush tax cuts as a whole expire."