There's always talk about the impact young voters could have in choosing the next president. But this truly could be a breakout year for them.

Among the factors: nearly 2-to-1 support for Barack Obama among 18- to 29-year-olds and a seasoned get-out-the-vote effort that has seen young voter participation steadily rising since 2000.

An AP-Yahoo News Poll conducted earlier this month found that, among 18- to 29-year-old likely voters, 60 percent supported Obama, 33 percent John McCain and 5 percent Ralph Nader. The poll had a margin of error of 9 percentage points.

When asked, "Do any of the following words describe how you feel about the upcoming presidential election?" 61 percent of the young respondents chose "interested," while 48 percent chose "hopeful."

But, able to choose more than one answer, only about a third of these likely young voters said they were "excited" about the election, and 47 percent were "frustrated."

These are the sort of answers one might expect from a group of voters who've historically been pegged as Election Day wild cards, but who've also shown they can be counted on — helping get both Ronald Reagan and Bill Clinton elected, for instance.

Show up big this time — and they could put Obama over the top. A lesser youth showing, however, would likely benefit McCain.

"So turnout suddenly becomes a pretty big ingredient," says Peter Levine, director of Tufts University's Center for Information and Research on Civic Learning and Engagement, otherwise known as CIRCLE.

That's especially true in key swing states, such as Florida, North Carolina, Ohio, Pennsylvania and Virginia. In North Carolina, for instance, the most recent tally available shows 579,858 new registrants who are eligible to vote this year. Many of them 20-somethings, they represent about 9 percent of the state's registered voters and could make a difference in a close race, particularly if they support one candidate more heavily than another.

The huge influx of new voters is part of a larger national trend.

Rock the Vote, which focuses on young voters, has registered more than 2.3 million voters this year, compared with more than 1.4 million voters in 2004, already a standout year for youth turnout.

In that election, about 47 percent of 18- to 24-year-olds voted, up from 36 percent in 2000, according to the Census Bureau. While their impact was not felt as greatly because their vote was more evenly split between George W. Bush and John Kerry, no other age group increased its turnout by more than 5 percentage points.