Step in the wrong direction or just step one?

The next complicating factor is Donald Trump’s promise to ensure that Americans don’t get abandoned in the process. That’s almost certainly why the AHCA does not eliminate the Medicaid expansion immediately, as House conservatives had hoped, and why this plan continues the practice of subsidies for health-insurance purchases. The need to extend both of those for the next few years stems from the difficulty of getting a full replacement program through the Senate; Republicans clearly hope to have a filibuster-proof majority after the 2018 midterms, but need to leave some measures in place before then.

That doesn’t necessarily make the AHCA the best bill that can pass under these circumstances, but it does explain why Republican leadership may have refrained from producing a final, full-scale repeal-and-replace bill in favor of a transition plan.