On the one hand, this strategy would probably motivate the blacks, Latinos, union members, and young voters of all races who turned out in huge numbers four years ago. Frustrated by the sluggish economy and disappointed by the gap between what Obama promised and was able to deliver, they need a reason to get excited, again.
On the other hand, the 10 to 15 percent of independent voters—nearly all of whom are white and middle class—who will determine whether he stays in office may well bridle if the president comes off as harsh and divisive. As Bill Galston pointed out this week, polls show these independents care more about economic growth and equal opportunity than they do about bashing Wall Street or closing the income gap. So the surge Obama would gain from his base, he might give right back if he alienates the almighty swing voters. I will leave it to brilliant statisticians like Nate Silver to figure out which group is larger—and in which purple states more of them reside.