Many congress members see the SAVE act as a no-win proposal. If they don't pass it, our November midterms will be rife with fraud so that we will never know who was truly elected, only who was selected. If they do pass it, the Left will likely explode with false claims of voter suppression, of partisanship, and even intimidation and violence fueled by all the virulent hate they can muster—which is quite a bit these days. They will work overtime to see that the supporters don't get reelected.
If congress holds off until they return from recess, they can then claim that they want to pass it, but it is too late for the November elections. Better to wait for later—or never.
By waiting, Congress can avoid a position on the SAVE act, and thus can avoid any blame or accountability. That would have the sinister effect of putting Trump in yet another set of crosshairs. It would force all the responsibility for a decision on Trump.
If he decides not to take action, then we would go into the November midterms with all the mechanisms for massive election fraud firmly in place. Votes recorded for non-citizens, deceased voters, voters registered at unqualified locations, voter registrations restored to the rolls after the voter moved, and all the other corruptions of our voter rolls will be used in conjunction with vote by mail schemes, ballot theft, ballot harvesting, drop box stuffing, to name just a few.
The internet connected systems will be used in conjunction with both state actor and local hacking to alter vote totals, duplicate and even manufacture ballots, assign fraudulent ballots to fictional voters on the rolls, and perform many other manipulations that so many good investigators have seen and reported.