President 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 resisted a deal to tame the debt that includes higher taxes, Obama's allies say.

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 reelection, 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 Jan. 20.

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 recession.