President Donald Trump speaks during a visit to the Sempra Energy LNG export facility on Tuesday, May 14, 2019, in Hackberry, Louisiana.

You can forgive Kirk Williamson, a Republican candidate for the state House this fall, for being pumped over his brief recent encounter at Louis Armstrong International Airport with President Donald Trump, which ended in what sounds like a fly-by, off-the-cuff endorsement.

Williamson, a candidate for House District 94, which straddles the 17th Street Canal between New Orleans and Metairie, told LaPolitics Weekly that Trump spotted him and suggested he run for office. When he told the president that he already was, Williamson said Trump responded "Good, you seem like a man who cares about his people and is a reliable Republican. I endorse you!"

Still, a few cautionary notes are in order.

For one thing, Trump surely had no idea that Williamson is challenging a fellow Republican, incumbent state Rep. Stephanie Hilferty.

And while Williamson told the news site that “this might be a first in the state of Louisiana's history where a sitting president endorses a person running for state representative,” it’s most definitely not.

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Thirty years ago, in a special election for a state House district in Jefferson Parish, then-President George H.W. Bush issued an endorsement of Republican candidate John Treen. So did his predecessor in office and the man he’d served as vice president, Ronald Reagan. And Bush’s son George W., a future president, came to town to campaign on Treen’s behalf.

Treen was no Bush, but he too hailed from a prominent GOP family; his brother Dave had been a congressman and Louisiana’s first modern-era Republican governor, and John was also active in party politics. But that wasn’t the explanation for all that high-level help.

The reason this race drew national attention was the identity of Treen’s runoff opponent, Nazi sympathizer and former Ku Klux Klan leader David Duke.

And it turned out that the presidential nod didn’t help; that contest marked the first and last time that Duke, who would go on to become a perennial candidate, convicted felon and Trump enthusiast, won an election.

So let’s just say that this is one presidential precedent that nobody should want to follow.

Follow Stephanie Grace on Twitter, @stephgracela.