Secret Service director Kimberly Cheatle is in the hot seat on Capitol Hill. In a House hearing today, she called the assassination attempt on former President Trump "the most significant operational failure" of the agency in decades. Cheatle is facing bi-partisan outrage and widespread calls to resign over the failure to protect Donald Trump at his Pennsylvania rally.        Vice-President Kamala Harris is not publicly speaking about the 2024 ticket just yet. In her first on-camera appearance since President Biden dropped out, she praised him and said his "legacy is unmatched." She made her comments at a NCAA event at the White House today. She is emerging as the front-runner to be the Democratic nominee for president.        More Democrats are coming out in support of Vice President Harris's presidential bid. Michigan Governor Gretchen Whitmer joined Midwestern Democratic governors from Illinois, Minnesota, and Wisconsin in endorsing Harris today. Whitmer said she's "fired up" to back Harris and will serve as co-chair of her campaign. Michigan is viewed as a must-win state for Democrats.       Delta is canceling or delaying more flights again today. Most airlines have recovered from last week's global tech outage, but Delta's CEO says technical issues are impacting Delta's crew-tracking software. He apologized for the problems.        NBA legend LeBron James will carry the Stars and Stripes at the opening ceremony of the Summer Olympics in Paris. James called it an incredible honor to be the first men's basketball player to carry the American flag at the Olympics. Team USA's female flag-bearer will be announced tomorrow.       "Twisters" is tops at the box office. The Glen Powell-led action flick is expected to gross 80-point-five-million dollars at theaters nationwide in its premiere weekend. Illumination's "Despicable Me 4" and Pixar's highly anticipated sequel "Inside Out 2" round out the top three films at the weekend box office.