President Obama pinned the blame on Republicans Tuesday for looming spending cuts that may be triggered by what was originally a White House proposal -- while a former leader of the president's deficit commission said it's Obama who's on the path to a "failed presidency" if he can't tackle the debt.

The president spoke Tuesday at the White House, urging Congress to come up with a short-term fix to cancel sweeping cuts to defense and other programs set to hit March 1.

"These cuts are not smart. They are not fair. They will hurt our economy. They will add hundreds of thousands of Americans to the unemployment rolls," Obama said. "This is not an abstraction -- people will lose their jobs."

The president ticked off a host of expected repercussions should the $85 billion in cuts for this year take effect. He said Border Patrol, emergency responders, FBI agents, airport controllers and others would all face cutbacks. He said teachers would be laid off by the thousands and America's military would be degraded.

As he has before, Obama urged Congress to pass a stopgap to allow for more time to pass a bigger package. But, with Congress out this week and many lawmakers resisting another attempt to kick the can on the cuts, Obama tried to cast Republicans as the ones responsible.

Obama suggested their resistance to his calls to pass a "balanced" package -- by closing tax loopholes for top earners and big corporations -- is the hold-up. He asked whether Republicans are willing to let hundreds of thousands of people lose their jobs "just to protect a few special-interest tax loopholes."

He blamed the current stalemate on "partisan recklessness and ideological rigidity."

House Speaker John Boehner, after Obama talked, claimed Obama was merely reinforcing what Republicans have been saying -- "his sequester is the wrong way to cut spending." Boehner and others note the so-called sequester -- which set up more than $1 trillion in sweeping spending cuts if Congress failed, as it did, to reach a compromise on deficit reduction -- originated in the White House.

"But once again, the president offered no credible plan that can pass Congress -- only more calls for higher taxes," Boehner said.

White House Press Secretary Jay Carney acknowledged that the idea was originally "put forward" by the White House. But he said the White House only pitched it as an "absolute necessity" in 2011 to avoid default over the debt ceiling, and noted Republicans "embraced" it at the time.

Shortly before he spoke, Obama was also dealt a blunt warning by former Republican Sen. Alan Simpson, who co-chaired the president's deficit-reduction commission.

Simpson warned that Obama "will have a failed presidency" unless he deals "honestly" with entitlements, saying programs like Medicare and Social Security must be dealt with in order to get the country on a sustainable path.

"If he wants to leave it alone and not deal with those two biggies, forget the rest of the stuff -- he'll have a failed presidency," Simpson told Fox News.

While Obama says opposition to tax hikes is holding up a deal, Republicans say Democrats' resistance to major changes to entitlements are a big part of the problem.

Simpson and Erskine Bowles, the former co-chairmen of the president's deficit-reduction commission who for years have been urging Washington to stop kicking the can, got in front of the president early Tuesday morning to push a plan of their own.

"Over the medium and long-term, our debt is projected to continue growing faster than the economy. It is simply on an unsustainable path," they said in a statement.

The two fiscal hawks pitched a plan to avert the looming spending cuts -- heavy cuts to defense and other programs that they describe as "abrupt" and "mindless" -- and instead enact a $2.4 trillion deficit reduction plan over 10 years.

A quarter would come from changes to health care spending, a quarter would come from closing tax loopholes and the rest would come from spending reductions including a stingier adjustment of Social Security's cost of living increases.

On tax reform, the plan presents a middle ground -- by using the savings from closing loopholes to both lower rates and bring down the deficit. By contrast, Obama has pushed to use that savings mostly to reduce the deficit, while Republicans have pushed to use it to bring down rates.

Simpson and Bowles cast their plan as building on the proposal from the president's deficit commission -- a plan that Congress never adopted and Obama never fully endorsed.

Obama, fresh off a three-day Florida golfing trip, pressed his own case during the event at the White House Tuesday morning. Emergency responders, a group of workers the White House says could be affected if state and local governments lose federal money as a result of the cuts, joined him.

The $85 billion in cuts, known as the sequester, will start taking effect on March 1 unless Congress acts. The White House says the sequester could derail an economy still suffering from high unemployment and sluggish growth.

Obama wants to offset the sequester through a combination of targeted spending cuts and increased tax revenue. The White House is backing a proposal unveiled last week by Senate Democrats that is in line with the president's principles.

But that plan was met with an icy reception by Republicans, who oppose raising more tax revenue in order to offset the cuts. GOP leaders say the president got the tax increases he wanted at the beginning of the year when Congress agreed to raise taxes on family income exceeding $450,000 a year.

A senior administration official later insisted the White House is not looking to raise tax rates for top earners, but does want to close deductions.

The official indicated the White House expects Republicans to eventually allow this despite statements to the contrary. Still, the White House sees the March 1 cuts as a real possibility, warning that the economic impact will be ugly.

The Democrats propose to generate revenue by plugging some tax loopholes. Those include tax breaks for the oil and natural gas industry and businesses that have sent jobs overseas, and by taxing millionaires at a rate of at least 30 percent.

Some Republicans, including House Budget Committee Chairman Paul Ryan, R-Wis., have advocated plugging loopholes, but as part of a discussion on a tax overhaul, not sequestration.

"Loopholes are necessary for tax reform," Ryan said Sunday on ABC's "This Week." `'If you take them for spending, you're blocking tax reform and you're really not getting the deficit under control."

The sequester was first set to begin taking effect on Jan. 1. But as part of the "fiscal cliff" negotiations, the White House and lawmakers agreed to push it off for two months in order to create space to work on a larger budget deal.

The Associated Press contributed to this report.