This year’s batch of presidential hopefuls are fighting over delegates as much as they’re fighting over voters. On Please Explain, find out who the delegates are, how the system works, and what superdelegates are.

Stephen Wayne is Professor of Government at Georgetown University and author of The Road to the White House: 2008. Elaine Kamarck of Harvard's Kennedy School of Government is currently a superdelegate, and previously was a superdelegate in 1984. She was an advisor to President Clinton and an advisor to the Al Gore presidential campaign.