San Antonio Spurs forward Tim Duncan, second from left, and his teammates arrive at the White House on Monday. (Brendan Smialowski/AFP/Getty Images)

First there was the flip-flop flap, then the no-denim directive, and now the tie-less tiff? Dressing up (or down) at the White House can be a tongue-twisting affair. Just ask Tim Duncan.

On Monday, Duncan and his San Antonio Spurs teammates were invited to 1600 Penn. to celebrate the team’s 2014 NBA championship. The presidential pat on the back is traditional, and everything was going by the book in the East Room — canned punchlines, Spurs memorabilia, trophy ogling — until it became clear that one of these things was not like the other.

While the rest of the Spurs were outfitted in Justin Timberlake-approved suits and ties, Duncan, 38, chose a navy sport coat over black slacks and a white button-down shirt sans tie. He went tie-less, people. And this was a big deal.

White House = Suit, said the experts we talked to, whether you’re Democrat, a Republican or an NBA superstar.

“It doesn’t matter. There always will be a level of formality attached to a head of state. The government’s formal; you can’t get around it,” explained Pamela Eyring, president of The Protocol School of Washington, which provides professional business etiquette and international protocol training. Eyring said that she coaches all of her clients visiting the White House to err on the dressier side, “meaning the pants and the jacket match.”

“When you dress up you’re showing respect for the White House,” added Eyring. “Yes, it might be boring. But it’s not time to be sexy.”

The general consensus among people who pay attention to these things is that Duncan is a “fashion disaster.” He’s a purveyor of plaid, oversized everything and denim with artisanal distressing, including but not limited to whiskering. Guys, he’s worn jorts. But none of that matters on the basketball court, of course. Duncan is a five-time NBA champion and 14-time all-star. When it comes to what he wears, though, it appears as if the clock has run out.

Duncan’s teammate Manu Ginobili said he didn’t attempt a sartorial assist. “I didn’t even try. It’s not his style. A tie is not his thing,” Ginobili told our colleagues in Sports.

Duncan proved that point in 2003 when the Spurs visited President George W. Bush after winning the NBA Championship. At that photo opp in the Rose Garden, Duncan wore what can only be described as a sort of updated leisure suit — billowy black pants with a matching button-down shirt. Monday’s outfit was a baby step up.

“It seems incredibly consistent for Tim Duncan,” said Pranav Vora, founder of Hugh and Crye, an upscale men’s clothier. “I’m sure he meant no harm. That’s simply who he is. But if I were a guest at the White House I would certainly be in a suit. You don’t want your clothes to take away from the moment.”

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