The math behind repealing and replacing the Affordable Care Act

Paul Ryan and other Republicans have to build support for GOP health care plan.

House of Representatives: 216

In the House of Representatives, Republicans must amass a simple majority to pass the legislation. While that threshold is typically 218 ayes when all House seats are filled, that number has decreased to 216 because of five vacancies. It could change if there are additional resignations or if any of the vacancies are filled through special elections before a vote.

The magic number: 21

While it currently would take only 21 House Republicans to kill the bill or force leadership into changes and several are already pressing leadership to make additional changes, Ryan predicted the bill will ultimately pass.

Senate: 50

The magic number: 2

With 52 Senate Republicans, if three or more conservatives vote against the bill, Pence won’t have a chance to cast a tie-breaking vote.