But why are young Americans rejecting Obama? I can think of possible sources. First, it may be because of the NSA spying revelations. As I noted back when the story initially broke in June, it was younger voters who were most likely to say they wouldn’t support President Obama because of what they’d learned. Second, young people are hit hardest by an economy that many Americans still think is weak – and the youth are at least partly blaming Obama.

Now, Obama’s approval with 18- to 29-year-olds, at 52%, still runs higher than it does on average. My guess is that among the 30- to 39-year-old subset, Obama’s approval is also higher than it is among all Americans. So, these voters can’t be described as Republican-leaning by any stretch.

The key for Republicans, however, is that by holding their deficit down among young voters, they could get to a majority by winning older voters by a large margin. Add on the fact that the young voters of tomorrow may not be nearly as Democratic as the ones today, and you get an idea of how the “Democratic majority of tomorrow” may never be realized.

Of course, a decrease in President Obama’s approval rating doesn’t necessarily guarantee Republicans can pick up support among those disaffected Obama backers in actual elections. Although presidential approval is highly correlated with election results, you still need to present some sort of a message that actually appeals to younger voters to win them over. I haven’t seen much evidence yet that Republicans are doing that.