By Tanner Curtis and

After a month focused on caucuses, primaries and debates in four states, the Democratic campaign is moving on. Super Tuesday, when 15 states and territories vote, presents a whole new map that could shake up the narrative of the race.

Senator Bernie Sanders is currently leading in the delegate count and in the polls, but former Vice President Joseph R. Biden Jr. can claim the most recent primary win. Senator Elizabeth Warren is pushing ahead despite recent defeats. Pete Buttigieg and Senator Amy Klobuchar ended their campaigns and Michael R. Bloomberg has yet to appear on a ballot.

New York Times photographers have followed the candidates every step of the way. Here is what they saw over the last month.