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President Barack Obama asked Congress Thursday for another $1.2 trillion increase in the nation's debt limit, a request that is largely a formality but which carries election-year implications

With the U.S. debt at about $15.2 trillion, it is now estimated to be larger than America's entire economic output. The proposed increase would boost the debt ceiling to $16.4 trillion, which should be enough to allow the government to keep borrowing until the end of 2012, or just after the presidential election.

The president's notification starts a 15-day countdown for lawmakers to vote on a resolution of disapproval to raising the debt limit.

The request was expected. It was the third and final such request the president was allowed under a deal the White House reached with lawmakers in August to prevent a government default.

But Republicans surely will use the request to criticize the president over his debt and deficit record in an election year.

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    "Washington's mounting debt is a drag on our economic recovery, and this request is another reminder that the president has consistently punted on the tough choices needed to rein in the deficit and protect important programs for American seniors from going bankrupt," said Brendan Buck, spokesman for House Speaker John Boehner.

    House Republicans quickly announced a vote would be set for Wednesday on what's known as a "resolution of disapproval" -- which signals that they don't support the request to raise the debt ceiling.

    But such a resolution would not clear the Democratic-led Senate, and the White House says Obama would veto an objection, anyway, in order to avoid default.

    Obama originally planned to make this request in December, but with Congress on vacation until mid-January, lawmakers asked the president to delay his request so they could vote on the matter when they returned.

    The debt limit is the amount the government can borrow to finance its operations. It has soared because the government has run record deficits over the past decade. In August, Congress and the administration agreed to raise the borrowing limit by $2.1 trillion in three steps. The deal was reached hours before a potential default on the nation's debt.

    Congress agreed to raise the debt limit by $400 billion in August and by another $500 billion in September.

    There was a flash of relatively positive news on the spending front Thursday. According to the Treasury Department, the federal deficit was lower in the first quarter of the 2012 budget year than the same period last year. Yet, the imbalance remains high by historical standards and should keep lawmakers debating tax increases and spending cuts through Election Day.

    The Associated Press contributed to this report.