Biden's debate performance spurs Democratic panic about his ability to lead party against Trump

Above all, Joe Biden’s allies have wanted him to demonstrate strength and energy on the debate stage this week to help put to rest questions about the 81-year-old Democrat’s physical and mental acuity. But on the biggest stage in U.S. politics on Thursday night, Biden did not meet their modest expectations. And by the end of the 90-minute affair, the Democratic president’s allies — party strategists and rank-and-file voters alike — panicked about his chances against former President Donald Trump this fall. They cited a debate performance punctuated by repeated stumbles, uncomfortable pauses, and a quiet speaking style that was often difficult to understand. Publicly and privately, Democrats questioned whether the party could or should replace him.