In a Washington Times article sure to spark discussion around the blogosphere, conservative pundit Matthew Sheffield has a column today alleging that left-leaning blogs contain far more profanity than their counterparts on the right.

Using George Carlin’s “seven dirty words” as a guide, Sheffield used Google to search the content of the top 10-most popular (in terms of web traffic) liberal and conservative blogs. (Note: he ruled out blogs that do not allow comments by readers):

Searching for Mr. Carlin’s seven words and some popular variants at the top 10 conservative Web communities yields about 70,000 results. That is dwarfed in comparison to the 1.9 million instances of profanity on liberal sites.

Things aren’t quite that clear-cut, however, since some Web sites have more pages than others. According to Google, the top 10 conservative sites have about 6 million pages, while the top 10 liberal sites have about 13 million.

Dividing the number of instances of profanity by the number of pages of the sites on which they appear, then multiplying the result by 100 yields what might be called a “profanity quotient.”

The top 10 liberal sites (Daily Kos, Huffington Post, Democratic Underground, Talking Points Memo, Crooks and Liars, Think Progress, Atrios, Greenwald, MyDD and Firedoglake) have a profanity quotient of 14.6.

The top 10 conservative sites (Free Republic, Hot Air, Little Green Footballs, Townhall, NewsBusters, Lucianne.com, Wizbang, Ace of Spades, Red State and Volokh Conspiracy) have a quotient of 1.17.

Conservatives, of course, would point to such findings as evidence of their superior level of intellectual discourse. Liberals would counter that it simply reflects the intensity of their justified anger at the Bush administration.

Sheffield contends that the “chasm” of profanity usage is probably due to the religious leanings of conservatives versus liberals:

More than likely, it is a reflection of how things are offline. Conservatives, especially those who are more religious, are less likely to use profanity in their daily conversation.

To me, this seems to be pure speculation — while it may seem like “common sense,” Sheffield offered no evidence to back up his conclusion. So I decided to put his thesis to the test by checking out the data.

I decided that the best way to determine the religiosity of liberals and conservatives was to check the exit polling from this year’s presidential primaries (most of which ask voters about frequency of church attendance). Since the primaries are known to be dominated by each party’s base (ideological liberals for the Democrats and ideological conservatives for the Republicans), the responses to exit polling would seem to be a good indicator of the liberal-vs.-conservative divide on religion.

Therefore, let’s take a look at seven “very red” (conservative Republican) states that had exit polling (Alabama, Texas, Utah, Mississippi, Georgia, South Carolina, and Tennessee) and compare the results with seven “very blue” (liberal Democratic) states that had exit polling (Massachusetts, California, Vermont, New York, Maryland, New Jersey, and Connecticut).

In the seven “very red” states (avg. 69.5 percent identified themselves as “conservative”) an average of just 4.9 percent of GOP primary voters said they “never” attended church. 67.8 percent said they attended services “weekly.”

By contrast, in the bluest states (avg. 55.2 percent self-identified as “liberal”), 25.6 percent of Democratic primary voters said they “never” attended church. 28.3 percent said they attended “weekly.”

Pretty much what one might expect.

But it’s not that simple, of course. It is important to note that polling shows Catholics — who traditionally tend to vote Democratic — are more likely to use profanity than their Protestant counterparts, even though they may not necessarily be any less religious.

Sure enough, the Catholic-vs.-Protestant numbers are reflected in the exit polls as you might expect: An average of just 9 percent of GOP voters in the reddest states identified themselves as “Catholic,” dwarfed by 72 percent who identified as “Protestant.” (The Protestant average would be even higher if not affected by the 90-percent Mormon Utah vote — only 3 percent of GOP voters in Utah are Protestants).

In the bluest states, Catholic voters narrowly outpaced their Protestant counterparts in the Democratic primaries: 34 percent identified as Catholic, while 32.7 said they were Protestants.

[For easier viewing, here's a PDF of the data in a spreadsheet.]

So, while the numbers on church attendance do seem to back up Sheffield’s religiosity-based explanation for the profanity gap, the significant Catholic-vs.-Protestant gap between Democratic and Republican primary voters may also account for a large part of the religious equation in explaining the foul-language disparity.

Then again, perhaps religion has nothing to do with it at all. Unfortunately, the other possible explanations — like “Conservatives have more sophisticated arguments” or “Liberals have more reason to be angry” can’t really be quantified or examined empirically.

Or maybe, as some prominent bloggers at the national liberal blog conference Netroots Nation recently argued, the incidence of profanity in the blogosphere is actually already declining:

Digby Parton, who writes on Hullabaloo.com, said she initially thought of her blog as an ephemeral form of conversation among friends and used vulgarities freely. But now she is read by a substantially wider circle and has cleaned up her language.

“I don’t use the same amount of profanity,” she said. “We’re taken much more seriously as a political force,” and she has a stronger sense that her words are “out there for posterity.”

Others disagreed, saying profanity was a justifiable response to the Bush administration’s policies:

Mr. Papa said his impulse toward vulgarity, including references to rape, was a reaction to that climate of suppression [under the Bush administration]. Besides, he said, “I curse a lot in my daily life.”

…Next on the panel was Duncan Black, aka Atrios of the blog Eschaton and a fellow at Media Matters, who questioned why certain words were perceived as bad when they were describing policies that were truly horrific.

“I’ve toned it down a little bit over the years,” he said, but he added that if he wants to use a certain word, he does.

…Using obscenities acts like a relief valve, [Papa] said, and “that’s the kind of thing that keeps a movement together.”