In the current environment there is no telling how many senators could wind up sick or quarantined as the Delta variant works its way through the unvaccinated (and to a lesser extent) the vaccinated. So it’s worth knowing that under the rules of the Senate, a cloture motion like the one that will be necessary to move to a final vote on the infrastructure bill requires 60 votes, period, not just three-fifths of those present and voting. This was an element of the compromise that made it possible to lower the cloture requirements from two-thirds of the Senate to three-fifths in 1975.

Yes, 67 votes were cast for cloture on the earlier motion to proceed to debate on the infrastructure bill in a July 28 test vote, but no one should be certain that the 17 Republicans who voted “aye” (including the wily Mitch McConnell) will be available to do the same as final passage approaches. For one thing, there will be votes on amendments that might have a bearing on support (ostensible or legitimate) for the underlying bill.