Have Democrats moved “from their 40-yard line to their 25” — that is, become somewhat more liberal — as Tom Mann and Norm Ornstein write in a recent op-ed and new book? Or have Democrats actually moved to the right, as Kevin Drum and Matt Steinglass argue?

Drum and Steinglass trot out some issues (gun control, tax rates) where “the Democrats” have moved to the right since the Clinton years. But there are a number of problems with that. The first, and most basic, is who “the Democrats” are.

In 1993 “the Democrats” included Richard Shelby of Alabama, who was a Democrat up until the 1994 election, although he voted pretty much down the line with mainstream Republicans. It included Ben Nighthorse Campbell, who voted somewhere in the middle until he switched parties. Bennett Johnston, John Breaux, Sam Nunn, Howell Heflin, Jim Exon, David Boren, Fritz Hollings . . . I’d say that collectively they were to the right of today’s Democratic moderates — and the 1993 equivalents of today’s moderates were there, too: Byron Dorgan and Kent Conrad, Joe Lieberman, Chuck Robb, Wendell Ford, Max Baucus, and others (note: I’m not looking up the actual ideological placement of these senators, but if you’re interested, you can find the data here).

Put it this way: I think it’s highly unlikely that Clarence Thomas would now get 11 votes from Democratic senators, as he did in 1991.

The other piece of this is that it’s often difficult to compare ideological positioning over time, especially when the status quo changes. Have Republicans moved to the left because in 1962 they opposed Medicare entirely but in 2012 they just want to convert it into a voucher system? In my view, there’s no easy answer to that, just as there’s no easy answer to whether Democrats have moved to the “left” or “right” on taxes, where the party as a whole generally supports more progressive taxes than the current status quo but lower rates than in the 1990s.

Overall, what you don’t want to do is compare what mainstream liberals wanted to do in 1990, or 1970, or 1950, with what the Democratic Party wants to do today — because back then lots of Democrats were not mainstream liberals, while today only a few are not. That makes the Democrats a more ideologically consistent and more liberal party, even if (and again, I’m not really convinced it’s the case) the issues their leadership is pushing have moved a bit toward the center. 

Note that, while there's a parallel process with the Republican Party — their liberal wing is long gone, and even the moderate conservatives are endangered — the process has been far more efficient for the GOP, and beyond that Republicans have often been led by their most extreme members of Congress. So the data say clearly that Republicans have moved farther to the right than Democrats have to the left.

I’d further argue that there’s a strong threat of irresponsible behavior among Republicans that has little or nothing to do with ideology at all. But none of that changes the fact that the Democratic Party has, in fact, grown more liberal over the years.