Cox said Lugar's "seeming contempt for gun owners in Indiana" could be seen in his refusal to join other anti-gun-control congressmen in backing two major legal briefs and his vote to confirm Elena Kagan to the Supreme Court, as well as the pro-gun-control Brady Campaign's 2006 endorsement of his reelection.
Lugar has looked increasingly vulnerable in recent weeks as a major flare-up about his living mostly in Virginia for the last few decades played out in the local media and Mourdock secured the backing of a number D.C.-based conservative groups including the Club for Growth.
The latest endorsement hurts even more: the NRA is popular in Indiana and its endorsement opens up a new line of attack on Lugar.
The NRA rarely gets involved in primaries, especially with incumbents, Cox said before ripping Lugar for being an exceptionally bad candidate for them. "This is certainly the only Republican race where we're endorsing against the incumbent in the primary," he said. "It's rare and not often where we are forced to be in a position of opposing an incumbent Republican."
The NRA has more than 80,000 active members in the state, according to Cox, and while he didn't want to "telegraph [his] punches" by disclosing their full battle strategy, he promised that the NRA will be heavily involved in the race.
"Our goal is to make sure every gun owner and everyone who respects freedom in Indiana understands there's a choice in this race," he said. "We're going to arm them with the truth. We're going to arm them with the facts."