There was overwhelming bipartisan agreement on Tuesday night that Gabrielle Giffords’ arrival for President Obama’s State of the Union address was the most compelling moment of the evening. Watch the footage and there’s simply no arguing with that—the Arizona congresswoman looked terrific. Her incredible comeback from a near-fatal shooting one year ago seems all the more remarkable each time she appears in public. (Not that she doesn’t face challenges ahead; a video she released over the weekend, in which she announced that she’s stepping down from her congressional seat to focus on her further recovery, is equally moving.) Her story is as potent a mix of painful and inspirational as there is, and you’d hope that it could stand as something of an antidote to the poisonous politics of the era.

Which is why some news out of Missouri on Tuesday was particularly stomach-churning: Just hours before Giffords made her way into the nation’s Capitol, an unknown provocateur was stalking the halls of the Missouri Capitol, tagging the doors of lawmakers—most of them Democratic women—with images of rifle crosshairs. From the Columbia Daily Tribune:

Orange stickers with an image of rifle crosshairs were found Tuesday on the office doors of several Democratic state senators, prompting an investigation by Missouri Capitol Police, Senate Administrator Jim Howerton said. The stickers were on the doors of all four Democratic women in the Senate—Jolie Justus and Kiki Curls, both of Kansas City, and Maria Chapelle-Nadal and Robin Wright-Jones, both of St. Louis, Justus said. One similar sticker was found on the nameplate outside the door of state Rep. Scott Dieckhaus, R-Washington. “If anyone thinks this was a prank, it is not a prank,” Justus said after discussing the discovery of the stickers on the Senate floor. “You don’t joke about someone’s personal safety.” A sticker also was found on the door of Sen. Victor Callahan, D-Kansas City and the Democrats’ floor leader.

Columbia-based reporter Sherman Fabes posted photos of the stickers that showed up at the lawmakers’ offices:

These are the pictures of the cross hair stickers that were on Sen. Curls’ Door twitter.com/ShermanFabes/s… — Sherman Fabes (@ShermanFabes) January 25, 2012

Sen. Chapelle-Nadal herself weighed in on Twitter and didn’t mince words, emphasizing her disapproval with “#DisgracefulCowards.” (Her tweets are “protected” but one was posted by St. Louis Activist Hub.)

It’s an apt moment to recall that Giffords once criticized Sarah Palin for using a map that literally put political enemies in the crosshairs. “We need to realize that the rhetoric…for example, we’re on Sarah Palin’s ‘targeted’ list, but the thing is, the way she has it depicted, we’re in the crosshairs of a gun sight over our district,” Giffords said in an interview with MSNBC in spring 2010. “When people do that, they’ve gotta realize that there are consequences to that action.”

We all know what followed.

Palin and other conservatives strongly rejected the notion that their imagery and rhetoric had anything to do with the bloodbath in Arizona a year ago. And no one can know what was truly in the deranged mind of Jared Loughner. But common sense says that when enough targeted political vitriol mixes with enough guns, bad things will eventually happen.