In 30 states and Washington, D.C., voters may declare a political party affiliation at the time of registration or change their affiliation at any point. Over time, shifts in these registration figures provide analysts with one of the most reliable indicators of trends in voter sentiment and political momentum.

Drawing on data from the nonpartisan data firm L2, the New York Times’s Shane Goldmacher conducted an in-depth analysis of the changes in these numbers over the past few election cycles. His findings paint a stark picture for the Democratic Party. It is in the midst of what he calls a “voter registration crisis,” with the party “hemorrhaging voters long before they even reach the polls.”