Consider the the current state of play: Unless the administration has some clever stratagem that pulls a legal rabbit out of a hat, it’s hard to see how the travel ban hasn’t already been effectively defeated. With every day that passes with the ban suspended, the case for its rapid imposition (stopping dangerous people from flowing here) as well as its overall rationale (to allow for a pause while better procedures are established) gets weaker. Any radical who was on the verge of coming here prior to the ban is presumably on his way now, and there’s nothing stopping the administration from setting up tighter procedures while the executive order case is proceeding, which makes the argument for re-imposing the ban at some later date if the case is somehow decided in the administration’s favor more tenuous.
The backdrop here is what appears to be a legal box canyon. If the administration did take its argument up to the Supreme Court, it seems likely that it would lose, assuming that the Court even takes the case now (it might very well pass, letting the inevitable preliminary injunction that will come from Judge Robart and the 9th Circuit play itself out). Maybe the administration can delay, waiting for Judge Gorsuch to get confirmed, but even with him on the Court, victory is not assured.