Harvard historian Niall Ferguson devotes his latest Newsweek column to the mix of television ads and on-the-ground get-out-the-vote efforts the presidential campaigns are employing this year.

Among his most interesting observations:

Maybe all this hyping of the ground game is a sign that the Obama campaign is worried. They have good reason to be. Four years ago, black voters turned out in unprecedented numbers for the president. More than 55 percent of African-Americans under 25 voted, compared with 47 percent in 2004. Just under half of young white voters showed up, much the same as in 2004. The story was similar for voters between the ages of 25 and 44: for the first time ever, African-Americans were more likely to turn out than their white counterparts. In the key state of Ohio, black turnout was above 70 percent. There was also a big jump nationally in the share of young Hispanics and young Asians voting.

Why might such people be less enthusiastic about Obama today? The answer is clear. This recession has hit young people hard, and it has hit young African-Americans harder than almost anybody. Black unemployment is 14 percent, nearly double the white rate. Black household incomes have fallen twice as much. If anyone has reason to heed Mitt Romney’s repeated criticisms of the first black president’s economic record, it’s his fellow people of color. They won’t vote Republican. But, disillusioned, they may stay home.