The fanfare surrounding the House GOP tax plan on Thursday masked a brewing storm in the other chamber.

Senate Republicans will have to sway a host of GOP swing votes as they try to jam through their own tax overhaul with almost no margin for error. Fiscal hawks are squawking about how tax legislation could balloon the deficit. Moderates like Sen. Susan Collins of Maine are worried tax cuts will disproportionately favor the rich. Even an Obamacare-related row could bubble up and trip up passage.


While a small handful of Democrats might get on board, it’s more likely Republicans will have to go it alone — meaning they can lose just two GOP votes before their tax bill tanks. Here’s a look at the groups of Republican senators that Majority Leader Mitch McConnell and the Senate’s chief tax writers will have to satisfy to get a bill through their chamber:

The deficit hawks: Bob Corker, John McCain, Jeff Flake

Of this trio of deficit hawks, only Sen. Bob Corker of Tennessee has flatly declared that he would reject a tax bill if it added even a cent to the deficit. But Sens. John McCain and Jeff Flake — two independent-minded Arizonans unafraid to buck their party — are starting to make more noise about the tax bill’s red ink.

McCain voted against the Bush tax cuts in 2001 and 2003 in part because of their impact on the deficit.

“The deficit went up,” McCain now notes. “Guess what? I was right.” (McCain, to be sure, is typically less deficit-minded when it comes to the Pentagon’s budget.)

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Newly unencumbered by reelection concerns, Flake has been increasingly warning against simply passing tax cuts — though he’s not prepared to reject any deficit-boosting bill just yet. He recalled how he was inundated with a flood of pushback from the alpaca lobby when he pointed out in a recent report that some taxpayers can claim alpaca as livestock for tax breaks.

“There is a reason for every credit, deduction, loophole in the code,” Flake said. “There’s a reason we haven’t done meaningful reform in over 30 years. And it’s gonna be tough, but we’ve got to do reform, not just tax cuts. Everything ought to be on the table."

Indeed, these aren’t the senators who are privately lobbying the Senate Finance Committee to keep certain pet deductions. Corker stresses that tax writers need to find $4 trillion in loophole closings and make the new tax rates permanent to make a tax reform truly substantive.

“To do it right, you gotta cut out so many provisions that are there,” Corker said. “I don’t want to be one of those people, like so many people who come to see us and say, 'I’m all for tax reform, but this is one provision that I don’t want changed,' which is everybody in the world.”

The moderates: Susan Collins and Lisa Murkowski

The death of Obamacare repeal was largely due to two moderate, vocal GOP women — Collins and Sen. Lisa Murkowski of Alaska — who had also teamed up this year to oppose controversial Cabinet picks and funding for Planned Parenthood.

They could prove equally influential in the coming tax fight.

Collins wants any tax overhaul bill to keep the top 39.6 percent tax rate for individuals making more than $1 million a year, and she sees no need to dump the estate tax that has long been a target of other Republicans.

The elimination of the state and local tax deduction, which has proved to be a big obstacle in the House, is also a concern for Collins, who called it a “double taxation.”

“I’m not drawing lines in the sand,” Collins said in an interview. “I’m trying to shape the package that comes out of the Finance Committee.”

The House plan released Thursday would eventually repeal the estate tax and implement lower limits for the state and local tax break. It would keep the top 39.6 percent level for individuals.

For now, leadership is less concerned about Murkowski, who secured a major perk in the budget measure that set up a tax overhaul: A chance to raise cash by opening the Arctic National Wildlife Refuge to oil drilling. But Murkowski’s independent streak and less-than-devout allegiance to Republican leaders — they declined to back her 2010 reelection bid as a write-in after she lost the GOP primary — always makes her one to watch.

The perennial leadership headaches: Rand Paul and Ron Johnson

Much like in the doomed Obamacare repeal debate, top Senate Republicans believe Sen. Rand Paul of Kentucky is the likeliest senator to reject any iteration of tax reform because it doesn’t go far enough.

Indeed, Paul is throwing out aggressive proposals that are likely to complicate the delicate overhaul efforts — such as enacting spending cuts to pay for lower taxes, rather than closing loopholes in the tax code. As part of the tax fight, he has also called for repealing Obamacare’s individual mandate — an idea that has since spread to Trump’s Twitter-happy fingers, but is not popular with the Senate’s chief tax-writers.

“I would prefer to stay out of the health care process because it’s tough enough to do a tax bill,” Senate Finance Committee Chairman Orrin Hatch of Utah said in an interview. “You add health care to it and ... it could just make it more difficult to pass the bill.”

Paul is also calling for a 15 percent corporate tax rate vs. the 20 percent rate in the House plan.

Though to a lesser extent than Paul, Sen. Ron Johnson of Wisconsin has shown he could be a thorn in the side of leadership, especially during the health care fight, and senior Republicans are watching him closely.

In an interview, Johnson laid out simple, broad priorities for a “tax plan that will grow our economy and recognizes … we have to make our business tax competitive with the rest of the world.”

The demanding conservatives: Mike Lee, Tom Cotton, Ted Cruz

Several other conservatives besides Paul aren't shy about making demands in high-profile policy fights.

The Obamacare individual mandate idea is also being pushed by Sen. Tom Cotton of Arkansas, who has the president’s ear on a wide range of issues, including immigration and foreign policy. When asked whether he will insist that a health mandate repeal be included in a Senate tax bill, Cotton responded with a grin. “We’ll see what the final package looks like,” he said.

Sen. Mike Lee of Utah is lobbying hard for an expansion in the child tax credit with Sen. Marco Rubio of Florida, and has a powerful ally in Ivanka Trump. Lee and Rubio said in a statement that the House did not go far enough with that tax credit: “We look forward to working with our colleagues to make sure working families are moved to the front of the line in the Senate bill.”

Sen. Ted Cruz of Texas has been less of a hassle for leadership lately, though he can't be ignored, either. But top Republicans seem less concerned about him mucking up their tax efforts.

“I believe our focus should be front and center on jobs — creating jobs, creating economic growth and cutting taxes for everybody,” Cruz said in an interview. “I think the key objectives should be economic growth, simplicity and fairness.”