Whether or not the $700 billion Wall Street rescue averts an economic catastrophe, it is certain to have an impact on the next administration’s political agenda.

The federal deficit, already projected to be around $500 billion for the year, could double because of actions by the Treasury and Federal Reserve to shore up Wall Street.

While presidential candidates Barack Obama and John McCain say the massive bailout for Wall Street won’t alter their White House agendas, the reality is that the next president will face an economic and political landscape dramatically altered by the credit market meltdown.

“The next president won’t have any money to do anything,” said Stanley Collender, a budget expert at Qorvis Communications.

Congressional staff aides told The Hill that even the defense budget, sacrosanct under the Bush administration, could face some cuts next year.

Treasury Secretary Henry Paulson has emphasized that the government may eventually recoup some of what it spends to purchase the “illiquid assets” that are clogging credit markets by reselling them once things calm down.

But the immediate jump in the deficit will likely cause heartburn among Blue Dogs and other budget hawks on Capitol Hill, who may now feel like they are being forced to swallow the costs because of dire warnings from the administration about the consequences of not acting.

Coupled with the actions already taken to shore up mortgage giants Fannie Mae and Freddie Mac, and the $85 billion bailout of the American Insurance Group, the annual deficit could rise to around $1 trillion this year, a big budget hole the next president will be hard-pressed to fill.

“I think the oxygen is effectively sucked out of the room for any spending proposals come January,” said Steve Ellis of the Taxpayers for Common Sense, a budget watchdog group.

Sen. Obama (D-Ill.) has argued that he could pay for his healthcare proposal, which seeks to extend coverage to 46 million uninsured Americans, by not extending the Bush tax breaks for the wealthiest earners.

But the budget constraints could make the Obama plan a tougher sell on Capitol Hill, according to Matt Bennett, vice president for public policy at The Third Way, a centrist think tank.

“Trying to move toward universal healthcare is going to get a lot harder” because of the cost, Bennett said.

Obama’s hopes to increase money for Head Start, the early childhood development program, or to increase money in general to K-12 could also be in jeopardy.

Sen. McCain (R-Ariz.), meanwhile, may have to pull back from his hope of extending tax breaks for the wealthiest Americans.