When the Supreme Court convenes Monday to open its new term, there will be 29 days until Election Day and one question on everybody’s mind: Will the justices once again find themselves in the middle of the presidential race? Before the election, the high court could be called to resolve emergency disputes over ballot-access measures or vote-counting rules. After the election, any challenge to the outcome would likely end up with the justices. Either scenario would transform a term that so...