Republican Senate hopeful Gary Emineth of North Dakota is refusing to back down after being busted for a series of hateful social media posts.

On Thursday, CNN’s Andrew Kaczynski unearthed a trove of vile social media activity from Emineth, including a Facebook post calling President Obama a “POS,” a retweet calling for “no more mosques in America,” a meme comparing food stamp recipients to animals, and a link to an article from far-right website Gateway Pundit that argued Hillary Clinton had DNC staffer Seth Rich murdered.

When confronted, Emineth backpedaled.

He claimed he didn’t know “POS” stood for “piece of shit,” telling Kaczynski, “You know what POS stands for in my world? I’m in the grocery business — point of sale. It’s the cash register.”

Given the general trend of his online activities, the idea that Emineth attacked President Obama by accident isn’t convincing.

Nor does Emineth appear to have any remorse.  Asked about the mosques post in a radio interview on Friday, Emineth said “So what?” He responded to the Bismarck Tribune with, “Bring it on. I’m going to say what’s on my mind.”

Emineth is one of only two people in the shallow bench of GOP candidates running to challenge Democratic Sen. Heidi Heitkamp.

Heitkamp, who is running for her second term, was previously thought to be one of the most vulnerable Democrats on the map. But Republicans haven’t been able to mount a serious challenger, and even her challengers admit that she is “well-liked” by her constituents.

Republicans seem unable to build a bench of passable candidates to challenge Senate Democrats, even in states where Trump won in 2016. From Pennsylvania candidate Lou Barletta hanging out with Holocaust deniers, to Missouri frontrunner Josh Hawley claiming “the sexual revolution” caused sex trafficking, Republicans are imploding all over the country just by being themselves.

Even in the reddest states, candidates like Emineth are being undone by their own extremism and poor judgment.