First, looking at the turnout number (14%), it needs to be noted that this is a low-ball number. CIRCLE doesn't just calculate the turnout within the Democratic Primary, they calculate it for the entire electorate. Last night there were no exit polls for the Republican primary, making it impossible for CIRCLE to crunch the data on that side of the aisle. So the 14% comes purely from Democratic turnout, but it's representative of the entire electorate. If CIRCLE were able to add in data from the Republican turnout, that number would surely rise.

Second, because there were no exit polls at all done in Pennsylvania in 2000 or 2004, we have no data against which to compare these numbers. We can, however, make a few very good guestimates.

What we do know is that turnout doubled in Pennsylvania last night, and that in 2004, the average youth "share of the electorate" was 9%. So in a year in which turnout doubled overall, young people gained a 3% greater share of all voters than they did in 2004. So youth turnout yesterday was likely more than double what it was in 2004.

As per usual, youth turnout also went heavily for Senator Obama. According to CNN Exit polling, 18 - 24 year olds broke for Obama 66 - 34%. Among 25 - 29 year olds the race narrowed, though Obama still carried the cohort 55 - 45%.

As I noted earlier in the week, Ohio and Pennsylvania are very demographically similar states. If Obama was to win or be competitive tonight, he needed youth to turnout be a greater share of the electorate in PA than it was in OH. That didn't happen. In Ohio, the youth share of the electorate was 3 percentage points higher, at 15% (pdf). There were likely a number of factors that kept youth turnout down.

There have been some reports of problems at the polling place, but a greater problem was likely the fact that many students - who have made up a disproportionately high number of young voters this cycle - missed the registration deadline, which bumped up against spring break, or they voted absentee in their home state during the previous contests. There is also the matter of brain-drain. Pennsylvania is one of the oldest states in the country, in no small part due to the fact that young college graduates leave the state to find work elsewhere. In other states, college-educated young voters have played a large role in boosting youth turnout.

While it's great news for Democrats, the Obama campaign, and youth activists that, in spite of those hurdles mentioned above, young voters turned out yesterday in greater numbers than every before, there was still room for growth. Young voters in PA made up 21% of the eligible electorate, so young people still did not vote in proportion to their share of the population. There was a 9% gap between what happened, and what was possible. Look at previous contests and you will see that this gap has occurred time and again this primary season. We've seen big gains - double, triple, even quadruple turnout - in every single state, but with the notable exceptions of Iowa and New Hampshire, these numbers have lagged behind young voters' share of the population.

Why is that so?

In Iowa and New Hampshire, which saw the largest share of the electorate and the largest turnout rate, respectively, among young people, youth organizers were moving full-steam ahead. Every 501c3, c4, and 527 was on the ground working to turn out young people. This has not been the case in the rest of the primary contests and caucuses. Progressive youth orgs just don't have the budget to run full youth campaigns during the primary season and no one thought this contest would go past February 5th. We were all caught unprepared for this and the youth vote in the remaining states is not turning out as much as it could be as a consequence.

There's a strong argument to be made here that the Obama campaign, for all the incredible work that it has done in energizing young people, needs help. It can't turn out the youth vote to the greatest degree possible on its own. It will need the support of outside youth organizations like YDA, The League, Young Voter PAC and more. If Obama donors who are maxed-out want to continue to help his candidacy, they could do a lot worse than directing some funds to these independent youth organizations that will be on the ground this cycle, and well after the polls close in November.

As I've said in my book and many times in the past, Millennials are a larger generation than the Baby Boom, and research shows that if you can get someone to vote for a party in their first three major elections, you can lock in their partisanship for life. Getting these young voters out now is about more than the Obama campaign. It's about building partisan loyalty and securing a progressive majority for the next 40 - 50 years. That's a worthwhile longterm investment.