Halfway through the Democratic National Convention, tonight the VP nominee Tim Walz pitches himself to the biggest crowd of his career, reaching out to a public around the nation that doesn't fully know him yet. He has a tough act to follow, because last night former President Barack Obama and his first lady Michelle both delivered barnstorming speeches that tried to recapture the energy around his 2008 campaign. Both also insisted that despite surging enthusiasm, it's going to be a very tight race. We get analysis from Chicago with reporter Kevin Liptak.?

Also on today's show: actors Martin Sheen and Melissa Fitzgerald discuss her new book, "What’s Next: A Backstage Pass to The West Wing"; Mesa, Arizona Mayor John Giles; US House Democrat Veronica Escobar?