The deep problem is that the Founders’ rationale for having the entire House come up for election every two years — which was to encourage turn-over — has backfired. Now it encourages retention. Off the top of my head, I can think of several factors that would drive this tendency like name recognition, a preference for continuity over change and a sense of comfort with the current office holder over a newcomer without a significant public record.
So, not surprisingly, the likelihood of re-election is now high, so high that the real election isn’t in November. It’s in the earlier primary. The way to knock someone out of their seat is to go after them in the primary — a tactic now so common that “to primary” has become a common verb.
This political gambit, of course, drives the parties to even greater polarization because it is typically the extreme wing that gets its knickers in a twist over the excessive moderation of the current congressperson and comes swooping in from the radical wing. We saw this in dramatic fashion when Eric Cantor, then the House Majority Leader, got tossed into the dumpster by an obscure economist named David Brat, whom no one had even heard of before and who, according to Cook’s analysis, is a virtual shoe-in for re-election. FWIW, Brat aligned himself with the extreme right-wing Freedom Caucus and has accomplished essentially nothing but be a reliable vote to block any legislation proposed by any Democrat.
This end-point seems to be an inevitable and troubling outcome of our form of government, one that the Parliamentary system avoids. The only solution I can see is for moderates to become so infuriated with the extremists that they primary them with more reasonable candidates. We’ll see if this strategy emerges in any meaningful way in the next couple of election cycles.