He doesn't have any authority what so ever as long as he lets black robed tyrants tell him what he can and can not do, when clearly he has Constitutional Authority.
Whether it is clear or not preliminarily depends on the view of his legal team, not someone off the sidewalk like you and me. Ultimately, of course, the question is decided by the USSC not some lower court.
There are always back-up plans and work-arounds; but it could be Game Over, if the dems, the RINOs, the deep state and the establishment with its MSM get a USSC decision that Trump is acting unconstitutionally.