A new poll has Bernie Sanders up 54 to 39 over Donald Trump. Meanwhile, Hillary Clinton no longer has a double-digit lead over Trump like she did just a month ago.
Bill Moyers and Michael Winship: Unless she steps down, the Democratic convention will be dominated by someone who represents everything that has gone wrong with Washington.
Valerie Tarico is a psychologist. She is the author of Trusting Doubt: A Former Evangelical Looks at Old Beliefs in a New Light. She is also the founder of WisdomCommons.org.