Now comes the difficult task of sellling that bill to the American people and to their own GOP colleagues, who are also reading the proposal for the first time.
To bypass Democrats, they want to pass their health care bill using a complicated process known as budget reconciliation. That means they'll only need 51 votes instead of the normal 60, but it also means the bill cannot add to the budget deficit.
Republicans will have to vote in lock-step to even reach that 51-vote majority.
Nobody expects any of the 46 Democrats or the two independents, Bernie Sanders of Vermont and Angus King of Maine, to support a Republican health care bill. That's part of the reason Republicans drafted their proposal in secret, to make sure they come up with something that all the Republicans can support and without giving Democrats much of a chance to pick it apart. But the Senate math starts with every Democrat as a "no."
That leaves Senate Majority Leader Mitch McConnell and his colleagues 52 Republicans votes. They can afford to lose just two Republicans and rely on a tie-breaking vote from Vice President Mike Pence.
If they make the bill too conservative on issues like repealing Obamacare's expansion of Medicaid or including a conservative priority to de-fund Planned Parenthood, they could lose some of the moderate members of their caucus. Three Republicans in particular are concerned the bill could erase elements of the Medicaid expansion that helped Obamacare insure so many new Americans. The Senate proposal would change the way the government pays for Medicaid and roll back the expansion after three years.
If all three of those senators oppose the bill, it dies. If two of them oppose the bill, Vice President Mike Pence would be needed for a tie-break vote in the Senate.
But if the bill doesn't do enough to control health care costs and roll back enough of Obamacare, Republicans will lose the support of some of the more conservative Republicans. There are more conservative Republicans than moderates, but a lot of the conservatives are also committed to party leadership. However, if Ted Cruz, Rand Paul and Mike Lee all voted no, the bill would fail.
Bottom line, Mitch McConnell's margin for error is very small and he doesn't have too many votes to play with.