Getty Images captured a photograph of a Romney supporter late last week wearing a shirt that read: “Put the White Back in the White House.”

The Romney campaign quickly disavowed that racist sentiment, but the T-shirt at a Romney rally appears to be more than an isolated incident. The closer America draws to Election Day, the more the examples pile up of ugly race-tinged attacks on President Obama.

Before the racist T-shirt, it was the empty chair “lynchings”, inspired by Clinton Eastwood’s speech to the Republican National Convention. And even before that, the racially-charged rumors that Obama was not really born in the United States bubbled to the surface again in the Alabama state GOP, the Republican convention, and even in a joke-y aside made by Mitt Romney on the campaign trail.

Indeed, racially-charged incidents have not been confined to the outer fringes of the Republican base. Mainstream conservative institutions have also flirted with arguments that could be perceived as appealing to white racial resentment—and that trend has only intensified in the final month of the campaign.

At the beginning of October, for example, Fox News, the Drudge Report and the Daily Caller promoted some “new footage” of a 2007 speech in which Obama allegedly made “racially charged” remarks to a predominantly black audience. But Obama’s actual remarks were completely innocuous, as msnbc’s Rachel Maddow argued at the time. The only reason conservatives were hyping the video as somehow revelatory, she said, was because they wanted to imply that ”people didn’t actually know [Obama] was this black, and if they had known he was this black they wouldn’t have elected him.”

Even members of the Romney campaign have faced accusations of deploying a neo-Southern strategy. Two days after the Daily Caller “scoop” was released, Romney surrogate John Sununu accused Obama of being “lazy”—an epithet with a long and ugly history when applied to African-American men.

The Romney campaign ran a major television commercial which some critics believe was designed to appeal to the racist stereotype of black people as lazy: the infamously false ”welfare for work” ad, which incorrectly claim the president removed the work requirement from Clinton-era welfare reform. As the American Prospect’s Paul Waldman said in early August, after the ad was first released, Romney staffers understood “the kinds of reactions people have when you start talking about welfare and those freeloading welfare recipients who are taking your hard-working money so they can goof off.”

The accusations of racially-coded language carry echoes of the late stages of the 2008 presidential campaign, when then-candidate Obama was also subject to racial epithets. In mid-October, less than three weeks before Election Day 2008, a California GOP organization circulated a mailing that depicted “Obama surrounded by racist imagery.” Even as early as May, the Washington Post wrote of Obama staffers and volunteers taken aback by a wave of racist incidents. Then, as now, the Republican campaign was accused of trying to make Obama appear “other” or un-American.

Both the Romney and campaigns struggled to generate enthusiasm among the GOP base with nominees who were less than beloved by hard-core conservatives. As late as September, Pew Research reported [PDF], “Roughly half of Romney’s supporters say they are voting against Obama rather than for the Republican nominee.”

When the Republican candidate commands relatively little loyalty among rank and file conservatives, the bulk of grassroots enthusiasm will inevitably come from opposition to the Democratic candidate.

The most enthusiastic members of the Republican base now appear to be those who fervently hate President Obama. While it is absurd to claim that all right-wing enmity to Obama is racially motivated, the evidence continues to mount of an ugly race-based streak through at least some of the most enthusiastic elements of Romney’s likely turnout.