Hillary Clinton and Donald Trump will meet for their third and final presidential debate at 9 p.m. ET, and Fox News’ Chris Wallace will moderate the match at the University of Las Vegas in Nevada. The stakes are high tonight, with just 20 days left until voters head to the polls. The candidates are both set to be on the offensive, a little more than a week after sparring in what the New Yorker’s John Cassidy dubbed “the nastiest presidential debate of all time.” Trump reportedly has invited President Obama’s half-brother, Malik Obama, to tonight’s debate, along with Patricia Smith, the mother of a Benghazi victim who has accused Clinton of “murdering” her son. Clinton has invited Meg Whitman, Hewlett Packard Enterprise CEO and former Republican California gubernatorial candidate, and Mark Cuban, the billionaire owner of the Dallas Mavericks. Topics that have been set include debt and entitlements, immigration, the economy, the Supreme Court, foreign hot spots and each candidate’s “fitness to be president.”