In the week since modest gun control died in the Senate, those of us who don’t think guns make the country safer have been inclined to blame a few cowardly senators whose votes could have shifted the outcome.

Unfortunately, the problem is bigger than that. Contrary to what then-Sen. Barack Obama told us in his inspiring breakout speech to the Democratic convention of 2004, there is a blue America and a red America. And the colors have been deepening over the decade since Obama spoke.

This isn’t an original thought. Journalist Bill Bishop coined the phrase “the big sort” in 2004 to describe the increasing political homogeneity of American living patterns. It comes as no surprise that some 60 percent of households in Montana own guns, compared with 13 percent in Rhode Island; or that, with similar populations, Missouri has six abortion providers and Maryland 34.