Photographs by Tony Cenicola, Todd Heisler and Calla Kessler.
Additional work by Gray Beltran, Alicia Parlapiano, Guilbert Gates, Isabella Grullón Paz and Rebecca Lieberman.
Polling data from ABC News/The Washington Post, Reuters, Monmouth University, Quinnipiac University, Fox News, USA Today/Suffolk, University of New Hampshire, CBS News/YouGov, CNN, The Des Moines Register, NBC News/The Wall Street Journal, Winthrop University. Numbers are through Feb. 20.
Polls conducted more recently and polls with a larger sample size are given greater weight in computing the averages. Data is for registered voters or likely voters, depending on the poll.