Rand Paul may not hurt Christie 2016 prospects, but they've fought before

"The main opponents for Christie are Jeb Bush and Scott Walker," said Julian Zelizer, a professor of political history at Princeton University. He called Paul's announcement "a marginal loss in terms of voters" that would shift from Christie to support Paul. Also, Christie and Paul won't likely share the same donor base, Zelizer said. But aside from donor and voter support, there's a third area where Paul's announcement could slightly ding Christie's presidential prospects: media attention. "It's a hit with media," said Zelizer. "(Paul's) trajectory has been upward and Christie's has been stalled at best, and it continues to hurt. Christie is in one of those moments where every nuance chips away." Momentum from media attention is valuable, Zelizer argued, and Christie needs to find a way to get some in what's expected to be a crowed Republican field.