Many a requiem has been written for "that hopey-changey thing," as Sarah Palin so memorably dubbed it. And to be sure, much of the griping about the president's harsh tone is the disingenuous phony outrage of Republicans who would prefer not to be its targets. But as Obama embarks in earnest on his second presidential campaign, deliberately invoking the echoes of 2008 as he does so, the contrast with his old image is especially stark.

From the beginning, the president's reelection campaign has taken a brutal, no-holds-barred approach that's sharply at odds with the conciliatory image that was the central predicate of Obama's entire pre-presidential political career. Whether or not the specific issue of Bain Capital ought to be off limits -- Booker has taken pains to clarify he doesn't think it should be -- there's no denying that Obama's 2012 campaign has seized every opportunity to turn the campaign toward sharply personal attacks of a type that the 2008-vintage Obama would surely have recoiled from. From Romney's treatment of his onetime pet dog to his high-school pranks to his income-tax rate, from the "war on women" to the "war on caterpillars," from "I like being able to fire people" to "I'm not concerned about the very poor," no potential controversy has been too petty, too rhetorically overblown or too out-of-context to be exploited to the hilt.

None of this is shocking -- it's how the game is played. But Obama once ostentatiously refused to play it. In June 2007, for example, when Obama's primary campaign distributed a memo titled "Hillary Clinton (D-Punjab)" detailing Clinton's connections to India, Obama publicly upbraided his staff, calling it "a dumb mistake" and "unnecessarily caustic." As the New York Times put it at the time, "The memo...raised quesitons about Obama's claims that he is above attack politics, which are epitomized by secretly distributing opposition research about a rival."

These days, the Obama campaign distributes harshly critical research memos as a matter of course. And the idea that it might be any other way is viewed as pollyannaish handwringing, or worse, doing the other side's bidding.

"This election, like all other elections, is going to be a choice between two candidates, two records, two visions for the country," the Obama campaign's press secretary, Ben LaBolt, said when asked about the campaign's sharp tone. "We have not heard an affirmative vision from Mitt Romney."

Democrats outside the campaign defend this approach as simple realism.

"The criticism of President Obama for the first year and a half on the left was that he wasn't fighting hard enough," Democratic consultant Karen Finney said. "From the perspective of the campaign, they are fighting hard."

Others point out that negative campaigning has always been a part of politics, and campaigns do it because it works.

"This is going to be an extremely negative campaign because it's going to be a close campaign, but that's not new," said Democratic consultant Steve Elmendorf, whose presidential-campaign experience goes back to Mondale '84. "A lot of people on both sides will say, 'Oh, this is awful, people are attacking each other,' but the reality is all campaigns work to take negative information about their opponent and make it part of the public discussion. The other reality is, voters process that information, and it changes their views."