A new Harvard poll finds that a majority of 18-29 year-olds disapprove of President Barack Obama’s handling of major issues, but nevertheless most of them (58%) approve of the president’s job performance generally, and many intend to help get him re-elected.

The poll was conducted by Harvard’s Institute of Politics, located at the John F. Kennedy School of Government.  Poll details are available here: www.iop.harvard.edu.

As we all know, Obama’s victory in the 2008 election was secured by his campaign’s ability to mobilize the youth vote.  According to the Institute’s research, nearly one-in-five (19%) young voters actively engaged on behalf of the 2008 Obama campaign in some way (in addition to voting).  In contrast, only six percent (6%) did the same for Senator McCain’s campaign. That’s more than a three-to-one margin.

Among the more popular activities of Obama volunteers: persuading friends (55%), participating online (30%), volunteering time (20%) and donating money (16%).

But in the wake of recent Republican gubernatorial victories in New Jersey and Virginia, many wonder whether the fabled Obama youth machine will stay motivated when the president comes up for re-election in 2012.

The answer, so far, is yes. When these most active Obama supporters were asked if they would engage in similar activities for him in 2012, 55 percent reported that they would be very likely to engage and an additional 30 percent indicated that they would be somewhat likely to engage.  Thirteen percent (13%) reported that they were either not very (7%) or not at all likely (6%) to engage in 2012.

How important is the youth vote? This age group will be the largest generation of voters in the country’s history when they all come of age in the next five years.

The Institute asked these same Obama volunteers their likelihood of engaging on political issues between now and 2012 on behalf of the president, and 34 percent indicated that they would be very likely to do so if asked, with an additional 43 percent somewhat likely.

It’s on specific issues that Obama runs into trouble, including the economy (52% disapprove), health care (52% disapprove) and Afghanistan (55% disapprove). I’ll look those in more detail tomorrow.