In Wonkbook today, I argued that the GOP primary has been bad for Mitt Romney, and the longer it drags on, the worse it’ll be. Over at Slate, Dave Weigel says the same thing. But some disagree. Indiana Gov. Mitch Daniels, for instance, told NBC News, “I’m in the camp that believes that these folks are being refined and improved by this very difficult process.” The theory there is that the 2012 Republican primary is akin to the 2008 Democratic Primary, which many believe strengthened the Obama campaign and bettered the candidate.

So let’s go to the numbers. The 2008 Democratic primary was surely long and bruising. But according to the Real Clear Politics polling average, on Feb. 28, 2012 — so, the equivalent moment in 2008 — Barack Obama was leading John McCain by 4.1 percent in head-to-head match-ups.

That lead persisted through most of the primary. McCain pulled even for a spell in March, but by April, and continuing pretty much straight through to the Republican convention, Obama remained a couple of points ahead of McCain. There’s no evidence that the long primary with Hillary Clinton caused any swing to the GOP. Indeed, Obama’s lead over McCain was larger in June than it was in February.

Now look at Real Clear Politics’ polling average for 2012.

Perhaps this will turn around for Romney once the primary is over. But as of now, there are essentially two viable interpretations of these numbers: Either Romney and the Republican Party are in a much weaker position than they were in 2008 or this primary has put them in a weaker position — perhaps temporarily — than than they were in at this point in 2008. I’m guessing the latter, as it’s hard to believe that Obama and the Democratic Party are in a stronger position today, when they have to answer for the economy, than they were in at this point in 2008, when everything was being blamed on George W. Bush.