Biden plans to warn Republicans not to use the debt limit as a bargaining chip.

President Biden plans to offer a wish list of Democratic policy proposals during his State of the Union address on Tuesday night, but the most pressing item on his agenda this year will require the cooperation of Republicans: raising the debt limit.

Seated behind Mr. Biden as he delivers his speech will be Speaker Kevin McCarthy, the president’s primary counterpart in the negotiations over the debt limit. Those talks, which started last week, are shaping up to be the biggest legislative fight in Washington this year.

The United States hit the $31.4 trillion borrowing cap last month, forcing the Treasury Department to employ so-called extraordinary measures to delay a default. Republicans are seeking to use the debt limit standoff to gain concessions from Democrats and force spending cuts. Democrats point out that raising the debt limit does not authorize any new spending and simply allows the government to pay for spending that Congress has already authorized. Economists roundly agree that it would be catastrophic for the economy if the United States did not pay its bills and defaulted on its debt by failing to make required payments to U.S. bondholders.

Although raising the debt limit is an urgent matter, it is not clear how much time lawmakers have to get it done. Treasury Secretary Janet L. Yellen suggested that her ability to move federal money around and stave off a default could be exhausted by early June, but that will depend on a variety of factors such as how fast the economy is growing and how much tax revenue comes in.

Mr. Biden has said that he is willing to discuss ways to reduce the deficit with Republicans but that those talks should not be tied to raising the borrowing cap, noting that Republicans approved stand-alone debt limit increases under former President Donald J. Trump.

A top White House official said on Monday that Mr. Biden would make the case in his speech that failing to raise the debt limit is not an option.

“This bedrock idea that the United States has met all of its financial obligations for its existence as a country isn’t something that anybody should be using as a bargaining chip,” said Brian Deese, the director of the White House’s National Economic Council. “It’s not a negotiable item.”

But Mr. McCarthy said on Monday that a “responsible” debt limit increase must involve policies that target wasteful spending and put the nation on the path to a balanced budget.

At least some Democrats appear willing to negotiate.

Senator Joe Manchin III of West Virginia wrote in a Washington Post essay on Tuesday that lawmakers should stop pointing fingers at each other and start focusing on cutting the debt. He called for a “bipartisan budget agreement” that would cap the annual growth of discretionary spending at 1 percent for the next 10 years, saving more than $1 trillion.