At some 887 pages, the legislation is a sprawling collection of tax breaks, spending cuts and other Republican priorities, including new money for national defense and deportations.

On July 3, Fitzpatrick was the only Republican opposed to the rule that set up a straight up-or-down vote on the Senate's version of the bill. The near unanimity came after Trump hosted skeptical lawmakers at the White House to answer their questions, worked the phones overnight and cheered the vote through social media.

With Sens. Rand Paul and Thom Tillis opposed to the package, GOP leaders can afford only one more defection. And multiple Republicans aren't yet sold on the measure.