U.S. Senator Bernie Sanders has been steadily climbing in popularity this year and is now tied with former Vice President Joe Biden for the 2020 Democratic presidential nomination among registered voters, according to a Reuters/Ipsos national poll. The online poll, released Thursday, shows that 20% of registered Democrats and independents said they would back Sanders over 11 other candidates to run in the general election against President Donald Trump, an increase of 2 percentage points from a similar poll that ran last week. Another 19% supported Biden, 12% said they would vote for Senator Elizabeth Warren, 9% backed former New York City Mayor Michael Bloomberg and 6% said they would support Pete Buttigieg, the former mayor of South Bend, Indiana.