In December, 2020, Prof. Laurence Tribe mentioned in a tweet the possibility that the states might be allowed to sue each other to overturn the results of the presidential election. He speculated on how many such suits were possible.
If we only allow lawsuits filed by individual states against other individual states, then there are C(50, 2) = 50 × 49 = 2,450 such possible suits.
If, however, we allow any combination of states to sue a given state, then each state is vulnerable to 249 − 1 suits. This is one fewer than the size of the power set (the set of all subsets) of the other 49 states. We eliminate the empty set from our count, as in such a case, no lawsuit would be filed.
There are 50 × (249 − 1) ≈ 2.81 e16, or 28.1 quadrillion such possible suits.