What’s Donald Trump’s campaign slogan?

Right. “Make America great again.” And how do you know that? Probably because of the hat.

The hat that prompted news articles when it debuted last year. The hat that Trump energetically tossed to to the crowd during an event on a battleship last September, before they appeared at — and sold out from — his campaign’s store in Trump Tower. The hat that’s become something of a uniform among Trump’s supporters, so much so that Trump derided a protester over the weekend who was wearing a red turban since he wasn’t wearing “one of those hats” — “and he never will.”

One of the more wonderful moments of the early Trump campaign was when a participant in a Frank Luntz focus group told the pollster that Trump’s goal “is to make America great again. It’s on his hat. And we see it every time it’s on TV.”

It’s on his hat and we see it every time it’s on TV. Except he doesn’t wear the hat any more, and so we don’t.

Republican presidential candidate Donald Trump speaks to supporters at a campaign rally Saturday, Nov. 28, 2015 at Robarts Arena in Sarasota, Fla. (AP Photo/Steve Nesius)

The last time Trump was photographed by the Associated Press wearing his hat during a campaign event was was last November in Florida. That’s nearly two months now without a sighting. The last time he wore that hat, Ben Carson was still in second place. The last time he wore the hat, George Pataki still thought maybe he could win.

So what happened to the hat? Donald Trump, marketer extraordinaire, recognized last summer that he had an opportunity to have his campaign slogan appear in every single photo in which he appeared. Find a photo of Trump from July or August, and there’s his campaign slogan. It’s on his hat. Like those backdrops they use at celebrity red carpet events, step-and-repeats, meant to ensure that sponsor logos appear every time a glamorous photo of Jennifer Lawrence shows up on TMZ. But it’s more like that time Macy Gray wore a dress with the release date of her album written on it. (Sept. 18, 2001, sadly for her sales.) Unavoidable.

The hat became a hot commodity. Trump introduced other colors, even one in camouflage. At first, there was a level of irony to it. Over time, it became more kitschy. By now, it’s like a dorky campaign button that some people wear earnestly, just another way of showing your support.

Since the hat debuted and Trump’s campaign became a juggernaut, awareness of the slogan stayed steady, as measured in Google searches. No one cared about searching for “make America great again” a year ago. Now people search for it all the time, often when seeking information about the hat itself. The hat and the slogan have their own life. Trump doesn’t need to wear it, any more than Nike needs to write “Nike” under their swoosh. The brand is known.

Of all of the signs that the Trump campaign has matured, I’d offer that this is one of the most clear. Not only because wearing a ball cap is unusual for the modern presidential candidate, but because Trump’s campaign has reached that level that Barack Obama hit in 2008. You know Obama’s slogan, too, I assume: “Hope” and “change.” You probably also know that Obama won.

What’s Hillary Clinton’s slogan? What’s Ted Cruz’s? What’s Bernie Sanders? What’s Jeb Bush’s? Trump’s hat may have outlived its usefulness for his campaign. But the idea — the concise slogan hammered home as frequently as possible — might still serve as inspiration for the campaigns of some of his competitors.