Writing at the Wall Street Journal, Andrew Cline explains why:
For starters, he appears to be drawing new voters. Polls that screen for "likely" voters might screen out many Paul supporters who haven't voted often, or at all, before. Many of Mr. Paul's supporters appear to be first-time voters. They will be able to cast their ballots because New Hampshire allows them to register and vote on the day of an election.But a strong New Hampshire finish won't just hurt other candidates. It might also mean Paul finally gets the credibility and attention from the media that even his astonishing fundraising prowess has, thus far, not been able to buy him.