IN THE 2008 PRESIDENTIAL CAMPAIGN, Barack Obama’s courtship of young Americans led to a newfound political enthusiasm among Millennials, a demographic group born between 1980 and 2000. This November, Obama for America (Part II), attuned to a surge of Hispanic and single-women voters, doubled down on that youth vote, orchestrating the best campus-based grass-roots operation in history. The strategy worked again: The majority of young voters chose to reelect the candidate their generation trusted in 2008.

As a result of the Obama campaign’s enormously potent political machinery — think frenetic door-knocking merged with tech-savvy e-mail and social-media blitzes — the president’s margin of victory among young voters increased in the most hotly contested battleground states, including Florida, Nevada, and Ohio. The turnout of young voters increased across the country, too. In the years ahead, Obama cannot let this powerful asset go to waste.