Tuesday night at 9 p.m. on PBS or your local web browser. I’m intrigued, and not just because the show’s publicist is e-mailing righty bloggers to promote it. With each new court-martial the “massacre” narrative crumbles a bit more, most notably in the investigating officer’s argument for dropping the charges against Lance Cpl. Stephen Tatum. Read that in the update to this post if you haven’t before. The nutshell version: Marines aren’t cops. The counterargument: In Iraq, they sort of are. Hence the persistent confusion over the Corps’ rules of engagement as a war dissolves into a peacekeeping/counterinsurgency mission. That’s the real story of Haditha, not Murtha’s nutroots fairy tale of rampaging Marines driven mad by long tours. Per the press release at the show’s website, “Frontline” seems to get that — emphasis on “seems.” We’ll see Tuesday.