UNDERWOOD, Iowa — With the Iowa caucuses just over a week away, the Bernie Sanders youth brigade is on the move.

Seven hundred college-age volunteers from across the Midwest and as far away as California are streaming into Iowa to help get the vote out. Organizers on Iowa campuses are reserving rooms to turn into phone bank centers, distributing campaign-provided toe warmers to the foot soldiers and playing Mr. Sanders’s spoken-word version of “This Land Is Your Land” to motivate them.

Ahead of Feb. 1, the day Iowa voters finally have their say, the Sanders campaign is activating “Go Home for Bernie,” a plan to dispatch a fleet of rental cars, vans and buses, if necessary, to carry students who are from Iowa back to their hometowns, where they will have maximum impact on the caucuses.

With his talk of free tuition, unabashed unhipness and calls for political revolution, Mr. Sanders has undoubtedly struck a chord with young people. But they are one of the least dependable constituencies in politics, and his campaign acknowledges that beating Hillary Clinton in Iowa will require harnessing their enthusiasm, overcoming their history of dismal attendance and replicating the 2008 turnout inspired by the historic candidacy of Barack Obama.