After months of negotiations, the details of the White House and congressional Republicans’ plan to overhaul the tax code, their next legislative priority after health care, are starting to emerge.

Republican leaders working on a tax reform bill have agreed to increase the lowest personal income tax rate from 10 percent to 12 percent; this bracket currently covers the first $18,650 in taxable income (after deductions and exemptions) for a married couple, and the first $9,325 for single people. In exchange, they’d double the standard deduction, according to a report from Axios’s Jonathan Swan.

The top rate, by contrast, currently paid by singles making $418,400 or more and married couples making $470,700 or more, would fall from 39.6 percent to 35 percent.

While the optics of raising rates on lower-income Americans while cutting the top rate are not great, this proposal is not entirely unexpected. House Speaker Paul Ryan — who along with Treasury Secretary Steve Mnuchin, National Economic Council Director Gary Cohn, House Ways and Means Committee Chair Kevin Brady, Senate Majority Leader Mitch McConnell, and Senate Finance Committee Chair Orrin Hatch makes up the "Big Six" team of Republican leaders working on the tax code — proposed exactly this in his Better Way tax plan in 2016.

While President Trump has waffled about the bottom rate at times, during the campaign he proposed a spike to 12 percent.

Defenders of this move claim it is offset by increasing the standard deduction. Swan reports that the deduction would increase to $12,000 for single filers and $24,000 for married couples, from $6,350 and $12,700 today, respectively. In other words, while tax rates would go up slightly, anyone who takes the standard deduction would have less taxable income (and more people would take it because of its increased value).

Will this hurt the middle class?

In their document outlining the Better Way plan, Ryan and his team argued that the standard deduction increase would hold middle-class households totally harmless: “The new standard deduction is larger than the current-law standard deduction and personal exemptions combined. This, in effect, creates a larger 0 percent bracket. As a result, taxpayers who are currently in the 10-percent bracket always will pay lower taxes than under current law.”

But whether that’s true depends on some other design choices the Big Six make in their tax plan.

Donald Trump’s final campaign plan combined this change with the complete elimination of the personal exemption, which currently provides taxpayers with a $4,050 deduction for every person in their household. He also proposed eliminating the head of household filing status, which gives additional tax relief to single parents and working adults caring for elder relatives.

That combination of policies resulted in millions of middle-class Americans facing a higher tax bill.

NYU Law’s Lily Batchelder conducted a thorough analysis of Trump’s plan during the campaign and estimated that 25 million individuals and 15 million children would see their taxes go up under the Trump plan, which accounts for more than half of all single parents.

And for many households, the increase would be significant. A single parent with $75,000 in earnings, two children in school, and no child care costs (because the kids are in school) would've paid $2,440 more under Trump's plan (which included a child care deduction that the Big Six plan might not). A single parent with $50,000 in earnings, three children in school, and child care costs of less than $6,000 would've paid $1,188 more.

Ryan’s 2016 plan avoided many of these problems. It eliminated the personal exemption too, but compensated not just by increasing the standard deduction but by boosting the child tax credit for families with tax burdens. It also retained head of household filing status for single parents. Both of those meant that far fewer middle-class families faced tax increases.

They’d all, intriguingly, greatly grow the “47 percent,” the group of Americans who face no positive income tax burden, a group infamously condemned by Ryan’s running mate Mitt Romney in the 2012 presidential race (the actual number is now more like 43.9 percent).

The Ryan plan would also cost about $3 trillion over 10 years, according to the Tax Policy Center. To make a tax plan revenue-neutral (which is necessary for a plan to be passed permanently with only 51 votes in the Senate), that hole needs to be plugged. And eliminating head of household status and the personal exemption raises a lot of money. That’s money that can pay for stuff like cutting the top rate from 39.6 percent to 35 percent, or the corporate rate from 35 percent to 20 percent, or the top rate for pass-through businesses from 39.6 percent to 25 percent (all expected elements of the Big Six reform).

If the Big Six makes that call, they’ll have designed a bill that redistributes money from middle-class households to high-earning individuals and corporate shareholders (and, arguably, some workers at those corporations). It would be a sharp departure from the Bush administration’s strategy of cutting income taxes across the board, which mitigated popular backlash against cuts for the rich. Instead, Republicans would be trying a new approach with much more explicit losers, including a big share of their voters.