There’s a TV ad that’s been running in Louisiana:

It’s evening and a mom is tucking in her baby. Getting a nice text from dad, who’s away on a trip. Then suddenly — dark shadow on a window. Somebody’s smashing the front door open! Next thing you know, there’s police tape around the house, blinking lights on emergency vehicles.

“It happens like that,” says a somber narrator. “The police can’t get there in time. How you defend yourself is up to you. It’s your choice. But Mary Landrieu voted to take away your gun rights. Vote like your safety depends on it. Defend your freedom. Defeat Mary Landrieu.”

Guns are a big issue in some of the hottest elections around the country this year, but there hasn’t been much national discussion about it. Perhaps we’ve been too busy worrying whether terrorists are infecting themselves with Ebola and sneaking across the Mexican border.

But now, as usual, we’re returning to the issue because of a terrible school shooting.

The latest — a high school freshman boy with a gun in the school’s cafeteria — occurred in the state of Washington, which also happens to be ground zero for the election-year gun debate. At least that’s the way the movement against gun violence sees it. There’s a voter initiative on the ballot that would require background checks for gun sales at gun shows or online. “We need to be laser focused on getting this policy passed,” said Brian Malte of the Brady Campaign.