Also from Tapped, this graph is pretty impressive:
Democrats have moved from an 11-point advantage among youth in 2004 to a full Democrats have moved from an 11-point advantage among youth in 2004 to a full 25 points. That's a remarkable leap. Political scientists argue that the more often someone votes for a party, the more that preference gets locked in. Each vote marginally increases your personal identification with the party you pulled the lever for. Three election cycles, and you're probably a partisan for life, or something near to it. Which means an advantage like this, though potentially temporary, also opens the door to a more enduring electoral edge with this generation.
