The GOP tax bill picked up support from two more senators Monday and resumed its lurch toward passage this week, despite last-minute concerns when another key senator raised questions that seemed to put his support in doubt.
Sen. Susan Collins of Maine and Sen. Mike Lee of Utah, two holdouts whose votes were likely but uncertain, offered strong endorsement for the package.
But Sen. Bob Corker (R-Tenn.), who was the sole GOP vote against the original Senate bill and then endorsed the final package only last week, expressed concerns over the weekend about a provision that would provide tax breaks for real estate developers.
Critics were quick to note that many lawmakers with sizable real estate holdings, including Corker, as well as President Trump, would personally benefit from the provision. Corker spent the weekend fending off attacks that he had traded his vote.
By Monday, Corker's office confirmed he would still support the tax bill, but he asked GOP leaders in the Senate for an explanation over how the provision made it into the final version.
"Because this issue has raised concerns, I would ask that you provide an explanation of the evolution of this provision and how it made it into the final conference report," Corker wrote Sunday in a letter to Sen. Orrin G. Hatch (R-Utah), the chairman of the Finance Committee. "I think that because of many sensitivities, clarity on this issue is very important and hope that you will respond in an expeditious manner."
The vote will probably be close. Sen. John McCain of Arizona — who is battling brain cancer — signaled he would miss the vote by returning home to Arizona this week.
Republicans can afford to lose only two votes in the Senate under special budget rules, given their 52-48 majority, leaving them little room to spare.
That has created an opening for opponents of the bill, who intensified their efforts to flood the Capitol phone lines and social media to pressure Republicans to halt the process.
But GOP leaders remained optimistic. "I'm confident we'll pass it," the GOP whip, Sen. John Cornyn of Texas, said Monday.
The House is expected to vote Tuesday, with the Senate to quickly follow that evening or by Wednesday as Republicans flex their majority in Congress to deliver for President Trump by Christmas.
As a precaution, however, Vice President Mike Pence again delayed a Middle East trip so that he can be on hand if needed to break a Senate tie.
Hatch responded in a letter Monday that he was "disgusted" with reports that "distorted" the bill-writing process, denying the real estate provision was jammed into the final bill at the last minute. He noted that such a provision was in the original House bill.
"It takes a great deal of imagination — and likely no small amount of partisanship — to argue that a provision that has been public for over a month, debated on the floor of the House of Representatives, included in a House-passed bill, and identified by [the Joint Committee on Taxation] as an issue requiring a compromise between conferees is somehow a covert and last-minute addition to the conference report," Hatch wrote.
In fact, the final version was a mash-up of the House and Senate bills, which included many similar elements but diverged greatly on treatment of so-called pass-through businesses.
Proponents said the provision was simply the result of taking the preferred approaches from both chambers. Cornyn dismissed reporting on it as a "false tale."
Still, opponents of the tax plan quickly dubbed it the "Corker kickback" as they tried to halt the bill.
"Every day, we learn more about the disgraceful special interest giveaways and loopholes that Republicans added to the GOP tax scam to enrich their donors and themselves," House Minority Leader Nancy Pelosi (D-San Francisco) said in a statement. "The GOP tax scam is not tax reform; it is a Frankenstein's monster of giveaways to the wealthy and powerful that will explode the deficit and pillage middle class America."
Despite polls showing Americans are largely ambivalent about the tax package, Republican lawmakers appeared determined to finish the biggest rewrite of the tax code in a generation, fulfilling Trump's promise of passage by Christmas.
Republicans remain confident that once voters learn more about the tax plan, they will appreciate the benefits. But for now, some lawmakers acknowledged they were receiving many complaints and criticisms from constituents.
"We're getting just crazy calls in our office," Rep. Dave Brat (R-Va.) said.
"The misinformation will die down," Brat said. "After it's passed, and you see the market keep going up and firms keep hiring, I think you're in good shape."
Outside analyses say the benefits of the steep corporate tax cut, from 35% to 21%, along with reductions in individual rates, will largely flow to corporations and the wealthy.
Republicans say the tax overhaul will spur economic growth and more than pay for itself by generating jobs and revenue. House Speaker Paul D. Ryan (R-Wis.) said Monday that the average family of four earning $73,000 a year would see more than $2,000 in tax cuts.
"Tax relief and reform will lift our economy, leading to higher wages for workers and more revenue for government," Collins said in announcing her support. "We must act now to reignite the engine of growth."
4:05 p.m.: This article was update with comments from Collins, Lee and Corker about their support for the bill.