system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does the "secret" Senate healthcare bill work, procedurally.
gpt
It's not so much procedure, as lack of procedure. The Constitution gives Congress the power to write laws, but it doesn't give many guidelines on how to do that. However, a lot of rules have been made over the years, but they aren't required, they're just what the Senate found useful/good practice.

In particular, however, there is a thing called reconciliation. It's meant to be an expedited way to pass bills, but they have to be related directly to the budget (so you can't just pass whatever you want). It also only requires 50 votes(plus a tiebreaker via the VP), instead of the normal 60 to be fillibuster proof.

The trade off is that the ability to fillibuster/slow down the bill is much lower, but again, everything has to be directly related to the budget (as ruled by the parliamentarian, a rules official). Right now, the prediction is that the minimum amount of floor time is about 10 hours for amendments etc.

After that, there aren't any rules. There's no rule stopping things from being done in secret- the only prevention is potential voter backlash, and convincing your fellow Senators to vote for something they haven't read (but which they'll be responsible for, regardless). You're also not allowing experts to comment (which is dangerous- it's *really* hard to get these right on the first go)

And in general, it's not that unusual for a bit of backroom negotiating to be done. It's much easier to compromise and haggle out of the spotlight. But it's never been done on this scale, for something like healthcare.