How the Bernie Sanders campaign grew, in two photos

As of this writing, the Iowa Democratic presidential caucus is still too close to call. Bernie Sanders and Hillary Clinton are separated by only a few tenths of a percentage point, and the winner may not be known for several more hours.

But before the final tally is known, it’s worth reflecting on what, for the Sanders camp, has been a genuinely amazing political achievement. Even if Bernie Sanders doesn’t ultimately win the Democratic nomination, what he did in Iowa—pose a real, sustained threat to Clinton, one of the most formidable politicians of her generation and the hands-down choice of the party’s establishment— should cement his place in history. As Slate’s Jamelle Bouie put it, Sanders is “the first socialist in a century to build a genuine mass movement in American party politics.”