Young voters supported Obama overwhelmingly in 2008. (Jae C. Hong/AP)

Ask any top Democrat to name the highest priority in the six final days of the 2014 midterm campaign, and you'll get a version of the same answer: The party must energize young and minority voters and get them to show up at the polls in far greater numbers than they have in recent non-presidential elections.

A new poll released Wednesday by Harvard's Institute of Politics suggests Democrats are failing miserably on that front when it comes to Millennials, the generation that helped Barack Obama make history in 2008. The survey of just over 2,000 18-29-year-olds broadly indicated a shift away from Democrats in 2014, leading the pollsters to declare Millennials "up for grabs" in the midterms.

But the most stunning finding came from the question of which party young voters wanted to see control Congress next year. Among all respondents, 50 percent chose the Democrats and 43 percent picked Republicans. But among the much smaller subset of respondents who said they would "definitely" vote this fall, the GOP won, 51 percent to 47 percent.

Who Would You Prefer to Control Congress?

The idea that young people–once identified as closely with Obama as any group except African Americans–would prefer a Republican Congress would have been unthinkable either in 2008 or 2012. The number is even scarier for Democrats when compared to 2010, when even in a Republican wave year the Harvard poll found that "definite" young voters preferred a Democratic Congress by a margin of 55 percent to 43 percent.

Yet it's not as if Millennials hold Republicans in high regard. Overall, more respondents disapproved of the congressional GOP than Democrats, and on key issues like the economy, foreign policy, immigration, and health care, Democrats earned slightly higher marks as well. But just like electorate as a whole, young voters most likely to cast ballots are favoring Republicans.

To John Della Volpe, the institute's polling director, the results indicate a return to a pre-Obama political dynamic in which young people did not favor one party strongly over the other. "They are more like the rest of America than we might have thought," Della Volpe said on a conference call Wednesday. "Today they're looking like another swing vote in American politics."

That Millennials have become disenchanted with the current state of affairs in Washington seems obvious. Asked who they blame for the "political gridlock" in the capital, a clear majority–56 percent– replied, "All of them." Nearly the same percentage said they would recall or replace the entire Congress if they could.

Who Is Responsible for Gridlock in Congress?

But Della Volpe argued the dynamic is more complicated. Millennials are not completely disengaged from civic affairs, but they want to see "tangible change," which participating in elections hasn't produced in recent years. "Young people are more likely to volunteer in 2014 than to vote in the midterm elections," he said. "That, to me, is one of the unique characteristics of this generation, that sets it apart from generations that have come before."

A generosity of spirit among Millennials should be applauded, but it's not much consolation for Democrats, who would much rather they show up to vote come November 4.