WASHINGTON – President Barack Obama is prepared to veto legislation to block year-end tax hikes and spending cuts, collectively known as the “fiscal cliff,” unless Republicans bow to his demand to raise tax rates for the wealthy, administration officials said.

Freed from the political and economic constraints that have tied his hands in the past, Obama is ready to play hardball with Republicans, who have so far successfully resisted a deal to tame the debt that includes higher taxes, Obama’s allies say.

Additional Photos

President Obama is ready to play hardball with Republicans, who have so far successfully resisted a deal to tame the debt that includes higher taxes. The Associated Press

In the days after the November election, the tables will be turned: Taxes are scheduled to rise dramatically in January for people at all income levels, and Republicans will be unable to stop those automatic increases alone.

If he wins re-election, Obama may finally be able to dictate the terms of a bipartisan debt-reduction deal. And if he loses to Republican Mitt Romney, Obama could make sure that tax rates rise before he hands over the keys to the White House on Inauguration Day in late January.

Administration officials declined to say whether the veto threat will stand if Obama loses the election.

Obama has never explicitly said whether he is prepared to let the new year arrive without taking action to avoid the cliff. Some Republicans, noting that the president has backed off demands for higher taxes twice in the past, are skeptical that he will stand firm now. But his veto threat challenges Republicans to a dangerous game of chicken over a fiscal event that would raise taxes for nearly 90 percent of households, slice deeply into military and domestic budgets, and probably spark a brief recession.

House Speaker John A. Boehner, R-Ohio, and other Republican leaders are already complaining about the president’s ” ‘Thelma and Louise’ economic strategy.” (In the 1991 film, the lead characters drive off a cliff in a 1966 Thunderbird convertible rather than surrender to police.)

But Obama’s threat has concentrated their attention. If the president emerges victorious on Election Day, top GOP aides in both chambers say Republicans would press him to abandon his quest to raise the top rates, in exchange for a more meaningful prize: a long-sought agreement to stabilize the debt, in part with significant new tax revenue. Virtually all Republicans have long opposed higher taxes.

“That’s the solution to the Rubik’s Cube: The current president wants additional revenues. Republicans don’t want higher tax rates,” said Jonathan Traub of Deloitte Tax, who served until this year as a senior aide to House Ways and Means Committee Chairman Dave Camp, R-Mich. Rewriting the tax code to increase tax collections without raising rates, Traub said, is “the only way to make the squares line up.”

Impediments to a deal are legion. Democrats pumped up on an Obama victory would resist compromise on the top rate, a point of partisan contention since it fell from 39.6 percent to 35 percent more than a decade ago as part of a package of tax cuts signed by President George W. Bush.

The Bush cuts, which reduced rates at all income levels, are set to expire Dec. 31. Obama and other Democrats want to extend them for income under $250,000 a year, maintaining the low rates for about 97 percent of taxpayers.

But Obama has been promising to eliminate the Bush tax cuts for the top 3 percent of households since the 2008 campaign, and liberals were furious with his decision to extend them in 2010.

Last week, Sen. Charles E. Schumer, D-N.Y., planted a flag firmly for returning the top rate to 39.6 percent, arguing that Obama has made higher taxes for the rich a centerpiece of his re-election campaign and that polls show the public overwhelmingly supports the Democratic position.

“We have worked very hard to separate tax breaks for the rich from tax breaks for the middle class, on both ends of Pennsylvania Avenue,” said Schumer, the No. 3 Democrat in the Senate. “The fact that we’re winning on this issue is a sea change.”

Some Republicans — such as Sen. Jim DeMint, R-S.C., a tea-party favorite — have conceded that an Obama election victory would amount to a mandate to raise the top rates. But Boehner recently ruled out that idea, and senior GOP aides say letting the top rate rise, even briefly, above 35 percent is a line party leaders cannot cross.