The Republicans are split between moderates and the Freedom Caucus.

The Two Cracks In The Republican Party

Donald Trump promised to come to Washington and get government working again. But the stunning failure of President Trump and Paul Ryan’s first legislative priority, the American Health Care Act, reveals that he underestimated a unique fracture of the modern Republican Party. Yes, moderate and very conservative Republicans were against the AHCA for very different reasons, making it difficult to find common ground. But there was also a second fissure that helped to take down the American Health Care Act. It was the same one that took down Eric Cantor and John Boehner and that has bedeviled government for years. Call it establishment versus anti-establishment, or belief in governance versus political purity, or fidelity to ideology over party, or more simply: the beliefs of the Freedom Caucus.

Conservative Republicans were not any likelier than the average House Republican to oppose the AHCA. Although the bill was never brought to a vote, we can still get a pretty good idea of who opposed it using whip counts from news organizations. Specifically, we’ll look at the Republicans who voiced concerns about the bill or who said they would vote against it according to The New York Times and The Washington Post.

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You can read about the caucus here: https://en.wikipedia.org/wiki/Freedom_Caucus. The are sympathetic to the Tea Party movement.