Amid the uncertainty for the middle class, the framework includes hundreds of billions in tax cuts that would directly benefit top earners and the wealthy, such as slashing the pass-through rate to 25 percent, repealing the Alternative Minimum Tax and ending the estate tax.

Pomerleau argued that the top rate would likely have to be higher than 39.6 percent to offset the pass-through cut -- currently, pass-through businesses are taxed at individual income rates as high as 39.6 percent. Other options to balance out benefits for top earners would be raising rates for capital gains and investment income, he said. The framework was silent on the treatment of capital gains and investment income. Both moves would likely encounter stiff opposition within the GOP.

The Senate Budget Committee on Thursday approved the vehicle for tax legislation, sending it to the full Senate for a vote this month. Republicans on the panel joined Democrats in trying to give more of a middle-class emphasis to the tax plan by including certain amendments. One calls on the Congressional Budget Office and Joint Committee on Taxation -- Capitol Hill’s official scorekeepers -- to provide estimates of how the tax legislation would affect people with different income levels.

CBO, the nonpartisan scorekeeper, proved to be a formidable referee for Republicans during the Obamacare repeal debate, finding that their health-care legislation would have caused millions to lose their coverage. It gave Democrats a powerful cudgel that helped scuttle the effort, even though many Republican lawmakers tried to discredit the budget office’s findings.

Improving Lives

Brady has stopped short of guaranteeing that no middle-class American would see a tax hike, but insisted that a tax bill would make things better for them.

“I guarantee you we are going to improve the lives of every American, driving down taxes and increasing their wages,” he told reporters last week.

Trump continues to sell his plan as a massive tax break.

“We’re having the largest tax cuts in the history of our country. In the history of our country,” he said Friday during a speech at the White House to celebrate Hispanic Heritage Month. “Does anybody in this room mind getting a massive tax cut?”

The crowd cheered.