If the tension wasn't obvious on their faces, it became apparent as soon as Sunday's presidential debate began.
As Republican Donald Trump and Democrat Hillary Clinton met midstage at Washington University in St. Louis they greeted each other — but did not shake hands.
Trump held a press conference 90 minutes before the debate with four women who either accused former President Bill Clinton of sexual assault — or in one case — a woman who was a child when Hillary Clinton defended in court the man accused of brutally raping her.
Twitter, naturally, noticed: