In 2008, voters under the age of 30 helped catapult Obama into the White House. Three years later, Obama’s approval rating is underwater with the demographic, which is becoming increasingly confident he’ll lose reelection.

According to a Harvard University poll out today, Obama’s approval rating with young Americans is at the lowest point of his presidency:

Despite a six percentage-point increase after the midterm elections that was reported in our Spring 2011 polling, President Obama’s job performance rating among young Americans, ages 18 to 29, is at the lowest point since we began polling the Obama administration in the fall of 2009. Currently, 46 percent of young Americans approve of the job the president is doing and 51 percent disapprove.

Obama has the same problem with young people that he does with basically every other demographic – the economy. According to the poll, 74 percent say the economy and jobs are their number one concern (lagging far behind are health care and education, at just 5 percent each). And out of all of the issues, Obama gets the worst marks on his handling of the economy (just 32 percent approve) and the federal budget deficit (just 30 percent approve).

But despite Occupy Wall Street’s attempt to tap into these concerns over jobs and debt, the movement and its class-warfare rhetoric hasn’t caught on with young people:

Approximately one-in-five (21 percent) young Americans are supporters of the the Occupy Wall Street movement. One-third (33 percent) say that they are not supportive, with 46 percent either unsure or refusing to answer the question.

In fact, Obama’s failure to live up the expectations he set in 2009 has actually caused young people to disengage from politics and activism, according to the poll:

The key findings in our survey suggest that Millennials are prepared to show their frustration not through strong support for the eventual Republican nominee, but rather by punishing President Obama and the Democrats by not engaging, volunteering or voting in the same volume that they did in 2008.

This survey should be an eye-opener for the Obama campaign, especially since it shows that his recent aggressive and partisan approach to job creation and taxes hasn’t helped improve his standing with young people. They are clearly looking for solutions, not class warfare rhetoric. Unless Obama makes some progress on the jobs front, the only way he’s going to be able to win back some of these disillusioned young supporters is by running a sharply negative campaign against the Republican nominee. With some luck, he may be able to scare some into pulling the lever for him, but there’s nothing he can do to generate the enthusiasm of 2008.