The Obama/Clinton divide you haven’t been hearing about

It’s a story (followed by an argument, followed by facts) about the biggest split within the Democratic Party. It starts with two groups.

Group A is a social minority whose political and cultural power exploded during the 1960s. As that decade went on and certain factions within Group A grew more militant, Congress pushed to extend voting rights to millions of disenfranchised people in Group A. Today, Group A is shrinking as a share of the population, though its leaders remain visible and outspoken – and though its members increasingly dominate pop culture and the entertainment industry.

Group B, by contrast, holds sweeping political power. Much of the machinery and benefits of government have therefore aligned in Group B’s interest, despite the fact that Group B’s members are about half as likely to live in poverty as those of Group A.

Though they’ve often joined the same political coalitions, Groups A and B face a deep cultural divide on issues from the war in Iraq to gay marriage. In this year’s Democratic presidential primary, those fissures have showed up in state after state across the country, with Barack Obama winning Group A by colossal margins almost everywhere he goes and Hillary Clinton winning Group B by margins almost as big. It’s such a clear split that it seems to threaten the party’s unity.

Oh, by the way: Though no member of Group A has ever been elected president, more than half our presidents have belonged to Group B.