From the start of the 2008 primary, young voters offered enthusiastic and historic support to Obama’s presidential campaign. Youth turnout likely made the difference between victory and defeat for Obama in the Democratic primary, and young voters provided most of Obama’s 2008 margin of victory: While Obama won 66 percent of 18-29 year old voters, he won just 50 percent of those 30 and older.

Although youth turnout is understandably cited as a challenge facing the Obama campaign, Obama’s actual support among young voters receives less attention. After all, polls continue to show Obama faring well among young voters, and Obama’s losses are commensurate with losses among other age groups. This is because of the diversity of the millennial generation. According to the exit polls, 40 percent of 18 to 29-year-old voters were non-white, compared to just 19 percent of voters over age 30. With Obama holding strong among non-white voters, his continuing strength among young voters is unsurprising. But Obama’s strength among all young voters obscures substantial declines in Obama’s support among young white voters, who today appear poised appear to vote much more like their parents and grandparents than they did in 2008.

Although young white voters were not nearly as supportive of Obama’s candidacy as young non-white voters, Obama still fared much better among younger white voters than older white voters. Four years ago, 54 percent of 18 to 29-year-old white voters voted for Obama, compared to just 41 percent of white voters over age 30.

Four years later, the Democratic hold on young white voters is in jeopardy. According to recent polls, Obama’s support among young white voters has collapsed, falling from 54 percent in 2008 to just 43 percent in last month’s Pew Research and Gallup polls.

Obama’s losses among young white voters are larger than any other demographic group provided by the two polls.

Given unrealistically high initial expectations, perhaps it is unsurprising that young voters are more disappointed by Obama’s performance. For many, disillusionment with the political process has accompanied increased hardship in life, as the hope and idealism of a bright future coming out of school dissipated into the reality of a harsh economy or taxing student loans, which might compound frustration with the Obama administration. The unemployment rate for 18 29-year-olds is well above the national average, at a dismaying 12.1 percent.

Those convinced that young voters would usher in a progressive political era might be surprised to learn that disappointment with Obama has led many young whites to switch their political allegiances to the GOP, not just return to the political sidelines. According to Pew, young whites have shifted a net 18 percentage points toward Republicans since 2008, leaving a majority of young whites identifying as Republicans by 2011.

Young voters continue to hold socially progressive views, at least in comparison to their parents and grandparents, but cultural issues have not translated into sustained support for Democrats. The bitter cultural debates of the mid-2000’s may be less salient than they were five years ago, as Republicans have de-emphasized gay marriage and social questions in favor of economic issues. It is worth noting that the Pew data on partisan affiliation preceded the GOP primary and Obama’s decision to endorse same-sex marriage, so there is some chance that renewed attention to cultural issues has resulted in a decrease in affiliation with the GOP or perhaps even renewed support for Democrats. Of course, Obama’s depressed standing with young white voters in recent suggests that events have not rebuilt Obama's support.

It is unclear whether Romney can capitalize on Obama’s losses among young white voters. Gallup shows that Romney is near McCain’s level of support, suggesting that Romney hasn’t made much progress toward consolidating the disaffected Obama ’08 vote. On the other hand, Pew actually shows Romney with 51 percent of white voters, which would represent a substantial gain over McCain's 44 percent in 2008, especially since Romney has not many won converts from other voting blocs. Of course, given that just 61 percent of young white voters say they will “definitely vote” in Gallup’s tracking poll, young, disaffected, voters might not turnout on either candidate’s behalf.

The diversity of the millennial generation ensures that Obama will continue to command a sizable advantage among young voters. If young white voters behave identically to their parents, Obama would still approach 60 percent of the youth vote, and potentially more, depending on its exact racial/ethnic composition. Even so, Obama will be hard pressed to repeat his decisive advantage among young voters without improved standing among young whites.

In a close national election, movement among any group could potentially prove decisive. Young whites constituted just 11 percent of the electorate in 2008, but that's more than the entire Latino vote and nearly as much as African Americans. The GOP primary and Obama’s decision to endorse gay marriage does not appear to have rejuvenated enthusiasm or support for Obama among a socially moderate cohort, and it is unclear what tools Democrats possess to rebuild their support. Given Obama's effort to build enthusiasm among Latino voters by halting deportations and and granting work authorization to young undocumented workers, perhaps we can expect the Obama campaign to announce a bold initiative on student loans over the next few months. Of course, even if Obama can regain the loyalty of young whites, it will still be a challenge to persuade them to vote at 2008 levels.