That's how Harry Enten reads the fact that, while Obama consistently leads in "registered voter" polls, Romney consistently tops the "likely voter" ones:
Let's say the gap between registered and likely voters is 3-5 points, similar to 2004, with the averages listed above being a correct reading of the electorate. It makes for a potentially very exciting election, as Republican strategist Liz Mair has noted: President Obama has spent millions on a supposedly unstoppable get-out-the-vote machine. Can Obama actually bring youth voters out as he did in 2008? Will Latinos really fulfill their supposed promise to become the next great force in American politics? Obama will have to focus on his base to ensure that they don't just sit at home. At the same time, he can't afford to alienate the centrist middle who are, no doubt, worried about the economy.