Signature matches. Late-arriving absentee votes. Drop boxes. Secrecy envelopes. Democratic and Republican lawyers already have gone to court over these issues in the run-up to Tuesday's election. But the legal fights could take on new urgency, not to mention added vitriol, if a narrow margin in a battleground state is the difference between another four years for President Donald Trump or a Joe Biden administration.

Both sides say they're ready, with thousands of lawyers on standby to march into court to make sure ballots get counted, or excluded. Since the 2000 presidential election, which was ultimately decided by the Supreme Court, both parties have enlisted legal teams to prepare for the unlikely event that voting wouldn't settle the contest. But this year, there is a near presumption that legal fights will ensue and that only a definitive outcome is likely to forestall them.