If the right-side majority (5 justices) hasn't changed its mind, then it's Roberts who is holdin' things up.
The Court gains nothing from "holding back" this decision (as it normally would have done until the very last day of the session, if not for the leak).
Might as well get it out there, and be done with it.
Once issued, it can't be "taken back" any time soon.
Do this now, and let the chips fall where they may.