A much lower percentage of young registered voters are enthusiastic about voting this fall than they were in 2008, according to a new Gallup poll.
The figures are a clear danger sign for the Obama campaign, which benefited from young voters four years ago and is counting on them again in 2012.
Just 58 percent of registered voters between the ages of 18 and 29 say they are "definitely likely" to vote, according to new analysis from Gallup, down from 78 percent who said they were in October 2008.
While comparing voter interest between July and October is not ideal, those numbers should concern the Obama campaign, since young voters are a cornerstone of their electoral coalition.
Obama won voters under age 30 by a 34-point margin in 2008. He still holds a 23-point edge with the group over Mitt Romney in Gallup's current tracking polls, a bit of a dip from his 2008 showing.
That advantage won't matter if the young voters don't show up to vote, however.
This post was updated at 9:05 a.m.