The rise of President Obama as the first black president has ushered in an uncomfortable era for the nation’s casual racists. While the urge to entertain friends and colleagues with historical stereotypes and hurtful prejudices has clearly become irresistible, what happens when that desire conflicts with one’s duties as a GOP office-holder, strategist, or activist? When is it appropriate to compare President Obama to a monkey, or make a quip about his presumed love of watermelons, for example? The quandary is only heightened by our new age of social media, in which private jokes can easily become public. As they continue to navigate this moral gray area, most Republican Party members are erring on the side of … erring — making or endorsing racially tinged or outright offensive jokes via e-mail, Twitter, Facebook, and old-fashioned paper, then awkwardly apologizing once they’ve made an ass of themselves. The latest example involved Young Republican vice-chairman Audra Shays, who posted an approving comment after a friend’s dubious joke on her Facebook page last week, but it’s a cycle that’s steadily repeated itself since Obama emerged in last year’s campaign.