Because the vote is so close, the outcome depends entirely on a multitude of judgment calls about which votes count, and which are counted, and how they shall be counted. The normal procedure in England and the democracies descended from England, or imposed by English troops, is that the major parties reach agreement before and during the vote count, on how the votes shall be counted. In the US however, you have a multitude of laws, laws which contradicted each other, and contradicted actual practice. For example a lot of perfectly good absentee ballots that were presented by the military in accord with the usual military practice were rejected this time because they did not comply with the letter of the law, even though they complied with custom and practice. The cause of the uncertainty is judicial imperialism. It is often said that Americans are litigious,but the cause of this destructive litigation is judicial willingness to unpredictably overturn existing practice.