As noted, some Republican in Louisiana wrote a short piece about his Catholic faith a decade ago in an obscure magazine and the text of that article is now being used against him in an attack ad run by Democrats. The running of this ad is wrong and if I were writing this for Street Prophets, I would say sinful.
First, there is no there there. Is it news that Catholics consider themselves to be the one true church? That they believe that all other attempts to understand the sacred are flawed? Specifically, that the Protestant critique of Catholicism holds no water. The piece is entirely in line with Catholic teaching and could easily have been written half a millennium ago. My wife (or any theology student of any faith) could have written it, but she would have done a better job and used a spell check. It is pretty much boilerplate. Nothing here that would alarm the Pope or surprise any Protestant who knows much.
Second, the ad lies. Jindal does not call Protestants depraved, he quotes Calvin who calls all humans depraved. Catholics do not believe that, since they are not Calvinists. Also he does not call them scandalous. It is a scandal that Christians are not united, since that is something Christ definitely wanted and prayed for. Using straight out lies in an ad is wrong and Rovian.
Third, trying to gain a short term advantage by exploiting disagreements among religions is wrong because it doesn't work to anyone's long term advantage. Does anyone think the Dems can win by becoming the party that defends the Protestants from those evil Catholics? Certainly not in Louisiana, Massachusetts or Wisconsin. Catholics are an important part of any Dem coalition. Bad enough that Dems are seen as the party of atheists, this makes them look like opportunists too.
Beyond that, why would a party that values inclusiveness try to promote dispute among religions? Will this improve our society? Will it help the national party win elections? The front page analysis of Jindal's piece could have been written by Jerry Falwell/Karl Rove, it was so full of twist and spin and the desire for some short term advantage.
Bad tactics, bad strategy, jut plain bad.