On July 21, President Joe Biden decided not to run for reelection, a big blow to Democrats who doubted his mental sharpness and ability to defeat Donald Trump. Biden confirmed on social media that he will continue as president until his term ends. He endorsed Vice President Kamala Harris as the Democratic nominee, potentially making her the first Black woman to lead a major party`s presidential campaign in U.S. history. It`s uncertain if other senior Democrats will challenge Harris for the nomination. Just days before his announcement, Biden tested positive for COVID-19 for the third time, with some congressional Democrats urging him to step down. Watch vidreo