Former Secret Service agenct discusses security lapse at Trump rally, Cheatle's resignation

Jeff James, former Secret Service Agent Jeff James Secret Service Director Kimberly Cheatle testified before a House committee last week, then resigned over the lack of security surrounding the attempted assassination of former President Donald Trump. How important is it that she resigned? What went wrong- What do we know now that highlights the security lapses? What changes need to happen to secure the democratic process?