 Live from NPR News in Washington, I'm Corva Coleman. Vice President Harris holds her first event today after she was endorsed for the Democratic presidential nomination by President Biden. The president ended his re-election bid yesterday. He issued a statement saying it was best for him to focus on fulfilling his duties for the remainder of his term. Biden's decision comes just a month before Democrats hold their national convention in Chicago. NPR's Mara Liason says no clear challenger to Harris has emerged yet.