Trump and Biden tied in Iowa as Biden leads in Michigan and Nevada

With just three weeks before Election Day, the latest CBS News Battleground Tracker poll digs into three key states: Michigan, Nevada and Iowa. CBS News director of elections and survey Anthony Salvanto joins CBSN's Elaine Quijano with a look at how the numbers compare to the 2016 presidential race, and states that may potentially emerge as new battleground states as a result of 2020 presidential race.