Whatever the Supreme Court decides will make no difference whatsoever in this matter. That would be the case even if it were to decide that the law needed to be changed. Undoubtedly the response to any such decision would be for the British government to insist that any such action was the responsibility of the Northern Ireland government, and must be deferred until that was in a position to act.

Theresa May will do nothing, and wait for the next crisis. You can't move an object by pulling or pushing on a rope of sand.