Joe Biden, 2020 Democratic presidential nominee, center, and U.S. President Donald Trump, left, participate in the first U.S. presidential debate hosted by Case Western Reserve University and the Cleveland Clinic in Cleveland, Ohio, U.S., on Tuesday, Sept. 29, 2020. Trump and Biden kick off their first debate with contentious topics like the Supreme Court and the coronavirus pandemic suddenly joined by yet another potentially explosive question — whether the president ducked paying his taxes. Photographer: Matthew Hatcher/Bloomberg