Summary: Takes the Red/Blue state metaphor one step further. In depth analysis of political/social divisions in America.

Summary: (Wikipedia) Red states and blue states refer to those U.S. states whose residents predominantly voted for the Republican Party or Democratic Party, respectively, in U.S. elections, especially in the U.S. presidential elections of 2000 and 2004. Only three states (New Mexico, Iowa, and New Hampshire) shifted parties between these two elections. In the latter contest, 31 U.S. states were"red" and 19 states were"blue," though 12 of those"red" states were"blue" as recently as 1996.

Summary: The Red Blue Divide at a surface level is a reference to the customary colors on TV result maps after a Presidential election has been held. Republican wins are commonly depicted in Red, Democratic wins are commonly depicted in Blue. But, the phrase really refers to a deep cultural divide that splits America.