New Jersey first lady Tammy Murphy, a Democrat running for U.S. Senate, on Wednesday unveiled her first campaign ad, a gun-safety message filmed outside NRA headquarters in Northern Virginia.

The big picture: Murphy is fighting Rep. Andy Kim (D-N.J.) for the seat now held by Sen. Bob Menendez, who's facing federal corruption charges.

Why it matters: The ad — called "Cowards," running on cable, streaming and digital platforms — is aimed at Democratic activists voting on endorsements at county conventions.

Zoom in: "They know their guns are killing our kids, but they don't care," Murphy says in the ad.

• "And weak, pathetic politicians refuse to stand up to them. In the Senate, I'll fight for universal background checks, to end immunity for gun makers. And let's ban military-style assault rifles once and for all."

The bottom line: "I'm Tammy Murphy, and I will make it my mission to take down the NRA," she says at the end. "I can't be bought, I won't be bullied, and that's why I approve this message."

Watch the ad.