On this "Face the Nation with Margaret Brennan" broadcast, moderated by Margaret Brennan: Sen. Bill Cassidy, Republican of LouisianaSen. Bernie Sanders, Independent of VermontNational Institutes of Health Director Dr. Jay BhattacharyaNicole Sganga, CBS News homeland security and justice correspondentClick here to browse full transcripts from 2026 of "Face the Nation with Margaret Brennan."   MARGARET BRENNAN: I'm Margaret Brennan in Washington.And this week on Face the Nation: Can a fractured Democratic Party unite to flip the House and Senate in the fall?Plus, the challenges facing public health.As we hit the final stretch of the summer of '26, the Senate has wrapped up...