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.

This time, Senate Republicans were dead-set on making an expensive suite of pro-growth business tax cuts permanent. That required finding deep offsetting cuts, and the cold, hard calculus by the Senate GOP’s chief architects was that enough of their 53-member conference would ultimately swallow their protests and go along.