Senate Republicans have asked the Congressional Budget Office to analyze Sen. Ted Cruz's proposal for further health insurance deregulation, and they've asked for one estimate of a health care bill that includes his changes and one that doesn't, according to a GOP aide familiar with the discussions.

The bottom line: That would give Republicans a better idea of the impact of his proposal, which would let insurers sell health plans that don't meet Affordable Care Act standards — including, potentially, waiving the pre-existing condition rules — as long as they also sell plans that comply with all of the ACA insurance regulations.

What to watch: Among the issues CBO would have to weigh: would the non-ACA plans be cheaper, what would happen to premiums in the ACA plans, and what would happen to the cost of federal subsidies.