McConnell is trying to negotiate a compromise version by Friday and Corker said Thursday that it’s possible that deadline will be met. 

"It feels like there’s momentum right now," he said.

The draft legislation would eliminate a 3.8 percent tax on net investment income such as capital gains and dividends for people who earn more than $200,000 and couples with incomes over $250,000 -- retroactively, effective Dec. 31, 2016. Ending the tax would cost the federal government about $172 billion over a decade, the Congressional Budget Office estimated.

Rounds called for using the savings to expand tax credits for Americans who are currently ineligible for assistance because their spouses have employer plans that don’t cover them. The South Dakota Republican said GOP leaders have told him the proposal would receive a CBO score.

"If we could make a change in that, I really think we could help millions of people," Rounds told reporters after a Republican lunch discussion. "These are folks who get nothing."

Schumer Response

McConnell has said eliminating the new taxes created under the Obamacare law would put downward pressure on rising health insurance premiums. A McConnell spokesman didn’t immediately respond to a message asking if he’s open to keeping the net investment tax hike.

Collins, whose opposition contributed to forcing McConnell to cancel a planned vote this week, said she doesn’t think the tax cuts for the wealthy should be in the bill. She argued that some of Obamacare’s taxes increase the cost of health care and are worth repealing, citing the 2.3 percent sales tax on medical devices.

Democrats have pilloried the Republican legislation as a redistribution of wealth from the poor to the rich, noting nonpartisan estimates that it would cut Medicaid, a health insurance program for low-income Americans, by $772 billion over a decade, and that 45 percent of its $700 billion tax break would go to the top 1 percent of earners.

Senate Minority Leader Chuck Schumer said Wednesday that the GOP bill would "cut support for Americans in nursing homes, those suffering from opioid addiction, and those with a pre-existing condition to pay for a tax break for the wealthiest few."