In the struggle to control the U.S. Senate, one race in North Carolina — where the Republican incumbent, Thom Tillis, is trying to hold off his Democratic challenger, Cal Cunningham — could be crucial.North Carolina is a classic purple state with a split political mind: progressive in some quarters, while firmly steeped in Southern conservative tradition in others.Two bombshells have recently upended the race: Mr. Tillis fell ill with the coronavirus after attending an event for Judge Amy Coney Barrett’s Supreme Court nomination without a mask. And Mr. Cunningham’s image was sullied by the emergence of text messages showing that he had engaged in an extramarital affair.Jonathan Martin, a national political correspondent for The Times, talks us through the race and examines the factors that could determine who prevails.Guest: Jonathan Martin, a national political correspondent for The New York Times.For more information on today’s episode, visit nytimes.com/thedaily Background reading: North Carolina is a linchpin in the 2020 election — the presidency and the Senate could hinge on results in the state.Here’s how the critical senate race was engulfed in chaos in a single night.