Earlier this summer, few Democrats could have identified Gov. Tim Walz of Minnesota.But, in a matter of weeks, Mr. Walz has garnered an enthusiastic following in his party, particularly among the liberals who cheer on his progressive policies. On Tuesday, Vice President Kamala Harris named him as her running mate.Ernesto Londoño, who reports for The Times from Minnesota, walks us through Mr. Walz’s career, politics and sudden stardom.Guest: Ernesto Londoño, a reporter for The Times based in Minnesota, covering news in the Midwest. Background reading: Who is Tim Walz, Kamala Harris’s running mate?Mr. Walz has faced criticism for his response to the George Floyd protests. For more information on today’s episode, visit nytimes.com/thedaily. Transcripts of each episode will be made available by the next workday.