Why is Hillary running left?

This brings us back to Beutler’s argument that the decision to shift leftward is made by the Clinton campaign from a position of strength, and provides evidence of a belief that Obama’s coalition is both transferable and larger than the Republican coalition.

I would call this the optimistic interpretation (from a liberal perspective) of her moves, even if you accept that this is simply cynical gamesmanship on her part. The pessimistic interpretation would stem from one of the theses of my book, “The Lost Majority”: that Obama modified Bill Clinton’s coalition into a narrower, deeper one.  This enabled Obama to win a victory in 2008 that was almost as large as Clinton’s 1996 win without bringing Appalachians or working-class whites on board. The problem with such a coalition is that it doesn’t allow for much flexibility: At least for now, Democrats have to run up the score with different groups in order to win.

Under the pessimistic take, the Clinton Coalition is simply gone. Bill Clinton had managed to keep Appalachian voters and working-class whites in the Democratic camp through skillful positioning and a bit of luck. But over the course of the next decade, these voters finally broke with the Democrats. This occurred at the presidential level in 2004 and 2008, then occurred at the senatorial level in 2010 and 2014, when relatively conservative Democrats like Mark Pryor and Mary Landrieu found they could no longer win with a Clintonian formula (in fact, they couldn’t come close to winning).  This was a break that was a long time coming, but given that it has filtered down to congressional and even state legislative offices, it seems like it will be difficult to reverse.