And all of that would have to be squeezed into a $1.5 trillion budget hole, forcing lawmakers either to scale back cuts, phase them in, find more loopholes to close or identify other taxes to raise.

The budget resolution released on Friday does foresee a balanced budget within 10 years — but only by assuming trillions of dollars in unspecified spending cuts and projecting higher economic growth than is forecast by the nonpartisan Congressional Budget Office.

Republicans are counting on a surge of economic growth to pay for their tax plan, and the Tax Policy Center analysis does not account for those “dynamic” effects. The group’s analysts said that they planned to release another report soon that does account for growth, but that they expected those results to be similar.

In a preview of the partisan battles over the tax legislation to come, Democrats seized the analysis as evidence that talk of populism from Republicans is not to be trusted.

“This report on Trump’s tax scam is more hard evidence that the president and his out-of-touch millionaire advisers are executing a middle-class con job,” said Senator Ron Wyden of Oregon, the ranking Democrat on the Senate Finance Committee. “While this administration continues to peddle false claim after false claim, nothing can hide the truth that the only individuals benefiting from this plan are the president, his family and his highflier friends.”

Republicans quickly dismissed the analysis, saying the tax cut framework needs detail before it can be accurately assessed. A nine-page proposal for a tax overhaul, announced by Mr. Trump and Republican leaders in Congress on Wednesday, did not include income levels for its three personal income brackets. It left the door open to a fourth level of taxation for high-income taxpayers, and it did not specify the size of an enhanced child tax credit.