Beats me.
I'm puzzled why people think he had no option, if he intended to keep the matter alive. First, a matter is not killed by failed cloture. Second, if he wants to have another cloture vote, he could have voted with the losing side, and filed another cloture motion. Has the same effect.
It’s certainly not the only thing he can do.
He can allow the amendment to be offered on other bills too.
I suppose he’ll move for reconsideration after the August break after the Dems hear from their constituencies. Perhaps more damaging news will come out too.