Republicans are poised to pass a historic Tax Reform package after gaining support from two key holdouts in the Senate. Passage of tax reform would mark the first major legislative achievement for the Trump Administration and would be the largest overhaul of the US tax system since the Reagan tax cuts of the 1980s.

The two holdouts were Republican Senators Marco Rubio of Florida and Bob Corker of Tennessee. Support from the two Senators all but guarantees that Republicans will fulfill their promise of delivering a tax cut to the American people before Christmas.

Child tax credit

Republicans believed they had a done deal when Rubio announced he would oppose the package unless an increase, to the Child Tax Credit, was made. Rubio wanted an increase in the tax credit itself and a change in the way the credit is calculated so that poorer families would see an increase in the benefit reaped from the credit.

The last-minute bargaining drew the ire of some of Rubio’s colleagues, but in the end, they were able to strike a compromise: the formula for calculating the credit would remain unchanged but the credit itself would double from $1,000 to $2,000. Importantly, the limit on the amount of the refund that families could claim would increase from $1,100 to $1,400, something Rubio was pushing for.

(Under the plan, if families pay fewer taxes than the amount they can claim through the credit, the difference can be paid back to them as a refund.)

In the wake of the changes, Rubio announced his support of the bill. First daughter, Ivanka Trump, has been championing a bigger tax break for families with children for months, and Rubio has been involved in that effort.

Ballooning deficits

Corker had been holding out over concerns about what the tax reform package would do to the debt and deficit. Analysis has shown that the Republicans’ plan would add $1.5 trillion to the national debt over 10 years. Bob Corker has had very public differences of opinion with President Trump in recent months.

But in an unexpected about-face late last week, Corker announced his support saying that in the final analysis, he believed the package would be more beneficial to the country than harmful. The switch in vote guaranteed Senate Republicans the margin necessary for passage. The bill is expected to pass in the House with little to no drama.

Middle-class tax increases

The tax package is not without its detractors though. Studies have shown that most of the benefits of the plan will accrue to corporations and the wealthiest Americans. Many Americans’ taxes may actually go up under the plan, and the amount by which their taxes rise may increase over time.