Should the tax bill pass, the political status of McConnell and Republicans would improve, perhaps even soar. So would the prospects of holding the Senate in the 2018 miderm election. McConnell’s enemies would be shamed. And Bannon’s plan to turn Senate primaries into battlegrounds would probably be left in the dust.

But if tax reform fails—and there’s a real possibility of this—it would produce a political explosion. McConnell and his allies would suffer. The fragile 52-48 majority might fall apart. And calls for McConnell to resign would multiply.

But McConnell isn’t dead yet—quite the contrary. He’s declared that confirmation of federal judges—conservative judges, that is—will be his top priority. He’s promised Democratic tactics to delay or defeat a stream of confirmations will not work.

And there’s a lot he can do to strengthen his position and that of Republicans.