To win the presidency in 2016, Democrats must climb a steep hill: persuade Americans to keep them in power for a third straight term at a time of voter frustration at the status quo, heightened fear of terrorism and low approval ratings for outgoing President Barack Obama.

But they have a powerful force in their favor: demographics, and the fact that the party is strongest with groups of voters that are on the ascent–racial minorities, young people, college-educated professionals and secular voters.