The chart above on exit polls for the New Hampshire primary suggests something really weird. There is a stark split between older young voters and younger young voters.
Here's what I mean. 18-24 year olds went for Obama by 38 points, while 25-29 year olds went for Clinton by 2 points. That's a 40 point difference within what is arguably the same generation. And oddly enough, Edwards outperformed among 25-29 year olds, and underperformed dramatically among 18-24 year olds. It seems like Edwards and Clinton, with their partisan messaging, did really well among 25-29 year olds, whereas Obama cleaned up among the youngest set.
Now, generational politics is a weird subject I don't understand very well, but you have to assume that age brackets that bunch up with each other would share similar cultural assumptions. It appears though that 25-29 year olds think very differently about politics than 18-24 year olds. Let's call the younger group A and the older group B.
If you are a member of A, the earliest you could vote would be in 2002, though that election cycle was a horrific one for youth turnout, so in all likelihood the first ballot you cast was for John Kerry. About half of group A couldn't even vote in 2004, though most could vote in 2006. That means that the group is composed of a lot of first time voters and people who voted for a Democratic change in 2006, and got one, albeit one with largely no follow-through. People in group A lived much of their political lives as Democrats in an anti-Bush country, as Bush has been disliked strongly since 2005. For at least half of their political lives, they have been in the majority. A person in group A's experience as a Democratic young person is that everyone in your generation and in other generations agree that Bush sucks and that the war in Iraq is bad.
Group B, by contrast, is composed of people like me at the older range and people who were 18 on 9/11. It is in some senses a traumatized group. I cast my first vote in 1996 for Bill Clinton after the Oklahoma city bombings, saw the impeachment, watched the election stolen in 2000, heard how 9/11 changed everything and then saw it politicized during the 2002 midterms and the war debate, experienced the crushing 2004 election, and then finally voted for a victory in 2006 followed by cynical inaction. Our experience as young Democrats is that our leaders are impeached by crazy people, we are called traitors for opposing a stupid war the rest of the country supported for way too long, and that we get beaten in elections based on fear. Only about 25-45% of our lives have been spent in any kind of popular majority, with 55-75% of our time in a hostile minority opinion status.
In other words, people that are 25-29 are much more cynical than the youngest voters, and probably much more partisan. We don't think everyone can get along, because the impeachment, 2000, the war debate, and the 2004 election suggest otherwise. We remember what it's like to be hated and sneered at by powerful people, while the younger younger generation only knows what it's like to have pathetically out of touch leaders who lose elections.