WASHINGTON (NEXSTAR) — Republican leaders on Capitol Hill have not formally published a budget proposal for next year but that’s not stopping President Biden from hammering them over potential cuts.

In Maryland Wednesday, President Joe Biden pledged to fight Republican efforts to slash spending and cut taxes for the wealthy.

“Republican Congress have pledged that they’re going to extend Trump’s tax cut from previous four years of $200 billion tax cut. That was supposed to go away,” said Biden.

He said keeping it will add trillions to the federal deficit. The president has until the summer to strike a deal with congressional Republicans who are threatening not to raise the debt ceiling until Democrats commit to spending cuts.

“So where are they going to cut?” Biden asked.

That’s the big question. Right now, it remains unclear exactly what Republicans want slashed from next year’s budget.

Texas Republican Sen. John Cornyn said defense spending cannot be on the chopping block but said the Democratic spending spree must come to an end.

“The single biggest cause for the increase in the debt is President Biden and Democrats over the last two years,” said Cornyn. “He knows it’s unsustainable.”

A new congressional budget office report said the biggest contributor to the national debt is Medicare and Social Security payments.

The president and Speaker of the House Kevin McCarthy have agreed not to touch the programs. But the president is asking the speaker to release a Republican budget proposal March 9, the same day the White House is set to release its own.