In a piece on the dire position of today’s Republican Party, TPM Cafe reproduces a series of historical graphs showing the large, and in most cases growing, gaps in partisan identification across various demographic groups, with Republicans faring especially poorly among young people.

And indeed, if you look at the trend over the last decade or so, the picture looks pretty grim for them.  What actually jumped out at me, however, was the 30-year comparison. In almost every group, wide as the partisan ID gap was, it was typically about ten points smaller than it had been in 1976.

That may sound like thin consolation for a party whose recent trend line looks a lot like the Dow: “Not quite as reviled as we were in the aftermath of Watergate? Oh, joy.” But there’s at least some reason to think there’s independent significance to the three-decade benchmark.   As wonks will know, the late political historian Arthur Schlesinger believed that American politics—and the liberal/conservative pendulum in particular—tends to move in 30-year cycles. And that last nadir preceded the decade conservatives now look back on fondly as their Golden Age.

You’d have to be a pretty crude reductionist to conclude, from that alone, the right is now “due” for a resurgence, of course. Much will depend on the perception of Obama’s first term as a success or failure—a perception that in turn will depend in some measure on sheer chance. And there’s a vocal “full speed ahead” contingent within the GOP that seems determined to put the party through a real Behind the Music style rockbottom eperience.  One  the many ironies of politics is that a serious defeat often leaves a shrinking political coalition in control of the folks  least in touch with the center as moderates jump ship. Still, it does seem worth noticing that they’ve gotten out of worse spots than this before.