Senate Republicans don't just have to write a "skinny repeal" bill that can get at least 50 Republicans. They also have to write one that meets their savings targets under budget "reconciliation" rules — and they're not there yet, as of this morning. The Congressional Budget Office estimates released yesterday suggest that the bill, at least as originally described, could be as much as $55 billion short of the savings target, according to Loren Adler, a budget expert at the Brookings Institution.

• They need: $133 billion over 10 years in "on budget" savings
• They have: $78 billion
• At risk: Medical device tax repeal, possible addition of opioid treatment money

Why it matters: That's likely a major reason we haven't seen a bill yet, with the Senate "vote-a-rama" scheduled to start tonight. Two Senate GOP aides suggested that Republicans are still working on it, but that it won't be a major problem. One said the issues are "nothing that can't be easily tweaked." Another said simply: "We will hit the target."