So now David Duke is threatening to run against Steve Scalise. Talk about ungrateful.

If anything, the former state representative, Ku Klux Klan leader, and way-too-close-for-comfort gubernatorial candidate should be thanking the Metairie congressman for inadvertently shining the spotlight back in his direction. Duke’s been old news for more than a decade now, and a recent report that Scalise, then a state lawmaker, had once spoken to a Duke-founded group was about the only thing that could get people to pay attention to him again.

And if there’s one thing that’s obvious from everything that’s happened since, it’s that Duke thrives on attention.

Scalise, a rising GOP star who last year became House majority whip, would clearly do anything to put the matter to rest. He’s called his 2002 address to Duke’s European-American Unity and Rights Organization, or EURO, a mistake he regrets, and has done his best to move on — even as top African-American and Democratic leaders have continued to focus on the incident and on some of Scalise’s past votes, such as his reluctance to honor Dr. Martin Luther King, Jr. with a holiday.

Duke, though, is making the most of his unexpected moment. And what a moment it’s been.

Suddenly, he’s being ascribed with all sorts of power over the Republicans. MSNBC host Rachel Maddow even suggested that congressional leaders were standing by Scalise not because they like him, think he’s doing a good job or accept his contention that he’s opposed to bigotry, but to appease Duke, who has been using his renewed notoriety to claim that he has the goods on other politicians. Not bad for a man who had long been relegated to the political fringe.

And suddenly, Duke is once again in demand as a talk show guest, where he’s being treated as a fascinating figure. In an early January interview on CNN, Michael Smerconish suggested Scalise’s claim that he didn’t remember accepting an invitation from close Duke associate Kenny Knight just wasn’t credible, because who wouldn’t remember meeting with Duke’s group?

“I’m certainly going to remember the day that David Duke was on my television program,” Smerconish said.

Closer to home, host Jim Engster introduced Duke on his statewide radio talk show last week as “probably one of the best known Louisiana figures of all time.”

You could argue that Duke doesn’t deserve the airtime, but give Engster credit for this: He let Duke show himself to be just what he’s always been, a petulant, resentful, racist, anti-Semitic, self-regarding and seriously thin-skinned low-life.

In one choice bit, Duke insisted he pleaded guilty to underreporting income and bilking loyal supporters not because he did so, but because he couldn’t risk a trial given the “bias out there among certain elements of the population against me.” The Big Spring, Texas, prison where he served his time? Why, nothing more than a “federal gulag for political dissidents in America.”

When Engster asked whether diversity in America is a strength, Duke countered that “diversity is our downfall.” After the host described him as “reviled,” Duke chimed in that he was also “loved.”

And he repeatedly pointed to his past success in winning votes in Scalise’s district and elsewhere, enough to secure a legislative seat against a prominent Republican opponent, and enough to capture the majority of the white vote in losing races for U.S. Senate and governor. In denouncing Duke, he argued, Scalise was effectively calling his own constituents racist. Hence the threat to run against him, because, he claimed, Scalise has “betrayed his people.”

It’s a ridiculous proposition, of course, and Duke clearly said it to generate continued notoriety. The problem is that he’s got something of a point — not that Scalise is a “sellout,” but that Duke does have a history of winning votes. It’s why the Scalise story has legs, and why former Gov. Mike Foster bought Duke’s mailing list then covered it up, which in turn fueled conspiracy theories like Maddow’s. It’s why people still, even now, deign to listen to the man.

That’s not on the other politicians, or the media. It’s on the voters who pulled Duke’s lever.

Just a little something to remember, in the unlikely chance they someday have the opportunity to do so again.

Stephanie Grace can be contacted at sgrace@theadvocate.com. Read her blog at http://blogs.theadvocate.com/gracenotes. Follow her on Twitter @stephgracenola.