For the last month, the Romney campaign has been running with a new strategy: blatant appeals to racial resentment. The welfare ads, which falsely accuse President Obama of “gutting” welfare reform, were the first sign of this shift. It continued in subtler form with attacks on Obamacare — accusing Obama of taking from Medicare recipients and giving the revenues to his supporters — and became explicit again with last Friday’s “joke” about the president’s birth certificate.

At this point, in fact, Romney has stopped trying to hide the extent to which he wants to “otherize” Obama as a president for nonwhites. In an interview with USA Today this weekend, he defended the welfare ads by accusing Obama of offering waivers as a political calculation designed to “shore up his base.”

At best, Romney means Obama’s “base” is made up of welfare recipients. And the latest report from Pew Research provides insight into why the Romney campaign has adopted the Lee Atwater playbook for winning elections. Just five years ago, party identification among white voters was near parity — 46 percent identified as Republican, 44 percent as Democrat. Now, Republicans have a twelve point advantage among white voters, 52 percent to 40 percent. Overall, the GOP has become incredibly homogenous — 87 precent of self-identified Republicans are white, compared to just 61 percent of self-identified Democrats.

With blacks, Latinos and other nonwhites so adamantly opposed to the GOP, Romney’s only hope for winning the election is massive turnout from white voters. Indeed, according to Ron Brownstein, Romney needs to capture 61 percent of white voters to win, assuming they turn out at 2008 levels. Moreover, it seems clear Obama retains the support of a critical number of white voters. His approval rating reached 50 percent in the latest Post/ABC poll, and as Greg notes, he leads Romney in understanding the economic concerns of ordinary Americans.

The attacks on welfare and Medicare are crude, but they are one of the few things that could lead white voters — and downscale whites in particular — to doubt Obama’s concern for people like them. Which is why, despite widespread criticism and condemnation, Romney will press forward with these attacks.

Jamelle Bouie is a staff writer at The American Prospect. You can find his blog here.