A study by the Pew Research Center, being released Wednesday, highlights the eroding support from 18-to-29 year olds whose strong turnout in November 2008 was touted by some demographers as the start of a new Democratic movement.
The findings are significant because they offer further proof that the diverse coalition of voters Obama cobbled together in 2008 - including high numbers of first-timers, minorities and youths - are not Democratic Party voters who can necessarily be counted on.
While young adults remain decidedly more liberal, the survey found the Democratic advantage among 18-to-29 year olds has substantially narrowed - from a record 62 percent identifying as Democrat vs. 30 percent for the GOP in 2008, down to 54 percent vs. 40 percent last December. It was the largest percentage point jump in those who identified or leaned Republican among all the voting age groups.
Young adults' voting enthusiasm also crumbled.
During the presidential election, turnout among 18-to-29 year olds was the highest in years, making up roughly 20 percent of the voters in many states including Virginia and New Jersey, due in part to high participation from young blacks and Hispanics.
That percentage, however, dropped by half for the gubernatorial races in those states last November where Republicans celebrated wins as black groups pushed Obama to do more to soften the economic blow from mortgage foreclosures and Latinos saw little progress on immigration reform. Young adults were also the least likely of any age group to identify themselves as regular voters.
"This is a generation of young adults who made a big splash politically in 2008," said Paul Taylor, executive vice president of the Pew Research Center and co-author of the report. "But a year and a half later, they show signs of disillusionment with the president - and, perhaps, with politics itself."
Democrats saw evidence of this last November, when Republicans toppled Democrats from power in governor's races in New Jersey and Virginia. Young, minority and new voters who Obama pulled into the fold in 2008 didn't turn out at the same levels for the two Democratic candidates. The same thing happened in the Massachusetts Senate race last month.
The lesson: Neither party has a hold on 18-to-29 year olds. They tend to vote far less than other age groups, yet they have proven to be a powerful constituency if they are persuaded to vote. And that means the race is on by both Republicans and Democrats to make inroads into the next generation of voters.
Analysts say the findings reflect the fast pace at which young voters live their lives, and both parties should take note of their fickleness.
"If you don't respond to their needs, hopes or dreams quickly, they're gone," said Matthew Dowd, an independent political analyst who was a strategist in former President George W. Bush's 2004 re-election campaign. "They'll leave the playing field or switch their allegiance."
"They haven't become Republicans and they aren't solid Democrats. They're just looking for leaders who are where they are and will deliver," Dowd said. "Both parties have to be cognizant of the volatility of that group."
According to the Pew survey, large numbers of young adults said they personally liked the president but were dissatisfied with his rate of progress in changing Washington, such as improving the economy and fixing health care. Just 46 percent of 18-to-29 year olds said they believed Obama had changed Washington, compared to 48 percent who said he had not. Only baby boomers were more cynical, with 52 percent saying Obama had not changed the way things work in Washington.
The young adults also were the only age group in which more disapproved than approved of Obama's handling of the war in Afghanistan. Only 34 percent supported his decision in December to send an additional 30,000 U.S. troops to the region, while 50 percent disapproved.
Still, when asked why Obama hadn't done more to bring change, young adults were somewhat forgiving, with about 56 percent blaming the president's opponents and special interests; only 30 percent said Obama was the one at fault for not trying hard enough.
The findings are part of Pew's broad portrait of the so-called millennial generation, the children of baby boomers who came of age in the new millennium. Demographers believe this generation can reshape U.S. culture and politics because of their demographic size and political outlook.
Making up nearly one-fourth of U.S. voters, 18-to-29 year olds are less religious, more racially diverse and liberal on social issues such as gay rights. They are steeped in digital technology and social media, and are strong believers in the view that the government should do more to solve problems.
Nearly two-thirds admit to texting while driving, and more than 8 in 10 sleep with their cell phones by their bed.
Nearly 4 in 10 have at least one tattoo; about half of those people have two to five tattoos. Roughly 1 in 4 have a body piercing in a place other than an earlobe - six times the share of older adults.
About 37 percent of young adults are unemployed or out of the workforce, the highest share among this age group in more than three decades. A record share - 39.6 percent - was enrolled in college, and one in 8 millennials ages 22 and older say they had "boomeranged" back into their parents' home because of the recession.
The Pew survey is based on interviews with 2,020 adults by cell phone or landline from Jan. 14 to 27. The poll has a margin of error of plus or minus 3 percentage points for all respondents, higher for subgroups.