When I suggest that race plays a more-than-incidental role in the opposition’s implacable opposition to Barack Obama, some accuse me of playing the race card; others just roll their eyes at my lame excuse for Obama’s presidential failings. But it’s neither lame nor an excuse. It’s a reality. How could it not be? Consider:

• Richard Nixon’s “southern strategy” explicitly used race to appeal to southern white voters, pulling the old Confederacy almost overnight into the GOP (and driving blacks overwhelmingly to the Democrats).

• Ronald Reagan expanded that strategy to white working-class voters everywhere, and “Reagan Democrats” provided his margins of victory.

• In 2005 Republican National Committee Chairman Ken Mehlman apologized to the NAACP for his party’s efforts “to benefit politically from racial polarization.”

• But perhaps the most bizarre sign of Republican race polarization is Senator Thad Cochran’s last-ditch effort to woo black voters in Tuesday’s primary run-off against Chris McDaniel. Cochran believes African Americans will find the Tea Party-backed McDaniel even more offensive than him, and he appears to be correct. The cynicism is breathtaking, but the irony is that Cochran’s desperate pursuit of black votes may do more to build an interracial coalition based on  self-interest than did the election of a biracial president who appealed to our better natures across the grim line of race.

A discouraging thought, but as I look around the world I see idealism everywhere in retreat from the sectarian forces that would keep us apart.

But I’m not giving up.