Our tribalism is nearly complete

New Jersey is, by meaningful statistical measures, a modern “blue state.” Throughout the 20th century, it bounced between electing members of both major parties governor, including moderate Republicans Tom Kean and Christine Todd Whitman in the 1980s and ’90s. But this century, Chris Christie is an outlier. At the federal level, both of its senators have been Democrats since the ’70s, discounting appointments to fill vacated seats; this includes Bob Menendez, who comfortably won reelection last week despite spending the latter half of his term being prosecuted by the Justice Department for corruption.

Still, until recently, New Jersey had a tradition of sending some Republicans to Washington. With the exception of 2008 and 2016, it elected six of them to the House every election this century, with the state having either 12 or 13 seats to fill, depending on apportionment. This was not a national outlier: Winning what one could call “away games”—congressional races on turf mostly populated by voters of the other party—has been a determining factor of who controls the Capitol.

The ability to win such races, however, is fading. It has been for a while. Although tribalism seems like only the topic du jour because of Donald Trump, Congress was becoming more sharply polarized years before he entered politics. Instead, his rise to power correlated with an acceleration of this trend—going from something resembling a crawl to a sprint. Under Trump, this has meant a diminution of Republicans’ ability to win in blue states. But don’t forget that Democrats began having the same problem in red states during the Obama years.