The issue, which various members of the healthcare industry have said makes the bill unworkable, arose as McConnell moved to integrate the Cruz amendment into the broader bill, the Better Care Reconciliation Act. The amendment allows insurers to offer less-expensive plans that don’t have to comply with most of Obamacare’s wide range of regulations as long as they also offer a plan that is fully compliant. Presumably, people who have more medical needs would purchase the plans that are more expensive and cover more medical care, but it would mean that healthier customers could buy plans that include less and also cost less.

In a new twist, the final version of the amendment leaves in place Obamacare’s requirement for insurers in every state to have one single risk pool rather than one for sicker individuals and one for healthier individuals as had been originally envisioned. That means that as currently written, the Cruz proposal would be asking insurers to operate plans governed by two different regulatory regimes within a single risk pool. The novel idea comes with many complicated implications, has left even the most seasoned healthcare experts scratching their heads as they try to game out how this might work in the real world, and has left many inside the insurance industry uneasy.