The House and Senate have now passed their respective tax bills. Next, they have to figure out how to reconcile their differences.
The negotiations will happen in a conference committee, where Republicans from the House and Senate will get together to try to hash out a final plan. Once they do, both chambers will have to pass it again. Republican leaders and the White House want to pass a final bill by the end of the year and send it to President Trump's desk.
The House and Senate bill have their biggest features in common: They would both slash the corporate tax rate from 35 percent to 20 percent, a historic reduction in the taxes levied on businesses at a time when Americans support raising taxes on corporations.
But there are also some big differences, including how permanent this tax overhaul would be. The House bill makes its changes to the individual tax code permanent; the Senate bill would allow many major provisions to expire after 2025 in order to comply with Senate rules that limit how much a bill that can't be filibustered can increase the federal deficit.
The House and Senate have also structured their tax cuts for "pass-through" businesses, like LLCs or partnerships, completely differently. The pass-through issue almost derailed the Senate tax bill, so it will be an area to watch closely as the chambers work out a new bill.
No issue seems so big that it would derail conference committee proceedings, which almost never fail. But tax policy is fickle, and every percentage point change means millions or billions of dollars being shuffled around the US economy.
Here is what House and Senate Republicans need to work out.