When returns from RI last night began showing that Sen. Linc Chafee was winning his primary over conservative challenger Stephen Laffey, I bet more than one pundit arose from the sofa, cursing, and began rewriting a prepackaged column that paired Chafee’s demise with the Lieberman-Lamont primary in Connecticut as signs of partisan and ideological polarization.Perhaps some Republican chatterers will make the absurd claim that the results show the GOP is more open to centrist candidates than the Democratic Party. My colleague The Moose, an early riser, has already done a post offering a sunnier and more balanced take: Chafee’s win and Lieberman’s steady poll lead as an indie candidate indicate an appetite for centrist candidates across the board, with the different primary results being attributable to the ability of independents to participate in RI primaries. The Moose may well be right that Lieberman’s narrow loss in the August 8 primary would have become a narrow victory if indies could have participated; as always, close races make it possible to point to all sorts of different shoulda woulda scenarios (e.g., that Lieberman would have also won if he had foresworn a post-primary indie race altogether). But I wouldn’t overstate the “closed primary” factor. CT allows indies to switch their registration to participate in partisan primaries right up to Election Eve, and anecdotal evidence this year was that thousands of them were doing just that. But there’s a much bigger difference between the two primaries that should give pause to anyone making comparisons. Throughout the primary contest in RI, Republicans were deluged with polls showing Laffey getting absolutely killed in general election matchups with Dem candidate Sheldon Whitehouse; Chafee, while often trailing, was always close. That’s why national Republicans threw absolutely every available resource into helping Chafee. And by primary day, most of those voting for Laffey did so with an understanding that they might be tossing away a Senate seat at a time when Democrats were beginning to realistically think they could retake the Senate. In CT, by contrast, the implosion of Republican Senate candidate Alan Schlesinger meant that Democrats could cast primary ballots without any real fear of losing a seat. And that’s also why national Dems, even though most of them endorsed Lieberman in the primary, didn’t devote anything like the kind of effort on Joe’s behalf that GOPers made for Chafee (and why a lot of them who have since endorsed Lamont aren’t exactly kicking out the jams for him, either, given Lieberman’s pledge to stay within the Caucus if he wins). So I dunno if the two primaries can be accurately compared; there are too many missing links, or Lincs.