For most of the 15 years he's been famous, Tom Brady's appeal has been that of the cipher. You can project any sort of character you'd like on to him, because he has none. He's a tirelessly pleasant 220-pound set of teeth.
When a reporter from the New York Times visited Brady's house last year, he spotted a menorah in his kitchen. Brady is Catholic.
"[I] think we're into everything … I don't know what I believe," Brady explained. "I think there's a belief system. I'm just not sure what it is."
That was the Tom Brady everyone loved – a regular guy so spiritually underdeveloped he wasn't sure he could believe in believing, but could throw the hell out of a football despite it. Or perhaps because of it.
Since then, at age 38, Brady has begun the dangerous business of growing a public personality.
This started with the buffoonery of Deflategate. When forced to speak, Brady was his usual, evasively bland self, but there was an unfamiliar anger present. Brady was having his Howard Beale moment, only he wasn't shouting. He was simmering. You sensed the explosion was not far off.
Once he beat the NFL (and its proposed four-game suspension) in court and returned to the New England Patriots, he began displaying another token in his locker – a red ball cap that reads "Make America Great Again." It's the slogan of Donald Trump's presidential bid.
Brady had to know someone would notice. His locker isn't a locker. It's a shrine. Anything in it is a holy relic.
Once someone saw it, everybody wigged out. Tom Brady suddenly had an opinion. And it was not the opinion America wanted him to have.
No one asked him about it at first. Brady left the hat out there. He doesn't wear it. Not yet. Once he does, expect a small shudder to run through all the territory north of the Mason-Dixon line.
This week, someone finally got around to bringing it up: "[Trump's] a guy who likes winning. You think he's got what it takes?"
"I hope so. That would be great," Brady said, grinning like the cat who got the cream.
The reporters crowded around him hushed for an instant. They could not quite believe what they were hearing.
Brady pressed forward: "There'd be a putting green on the White House lawn, I'm sure of that."
Everyone laughed uncomfortably. The Tom Brady they want should be talking up Habitat for Humanity or raising money to send malaria nets to Africa. He should not be endorsing a huckster-slash-human emoji for commander-in-chief.
One headline nicely summed up America's reaction: "Tom Brady is Dumb."
Brady seems to be enjoying all of this. For most of his career, he's looked one plucked bowstring away from shattering. There's more of a twinkle to him now. He's knee-deep in his "I don't give a damn what anyone thinks of me" years.
If you are one of the people angry at Brady because his politics don't match your politics (the tiresome and unbridgeable fault line of our age), I'd suggest you're missing the point.
Everyone assumed Brady was the sort of guy who likes every candidate, because he can't tell one from the other. A go-along-to-get-along sort of guy.
If Brady wanted to make everyone happy, he'd have said nothing.
If he'd wanted to make most people happy, he'd have picked Hillary Clinton. People would assume it was pure cynicism, but the press and the commentariat would feel obliged to pat him on the head for it in any case: "Tom Brady is Smart."
If, on the other hand, Brady wanted to dispel his image as a milquetoast schmoe, he couldn't have managed it any better.
Lining up behind Donald Trump is the 2015 version of letting your freak flag fly. Benign and coddling leftie politics are the new conservatism. If you're the sort of person who wants to upend the status quo, Trump is your lever.
Sure, he's a dangerous loon. But where's the fun in linking arms with a non-dangerous loon?
This is the best sort of politics – satirical. It's provocation and mischief. Brady is pranking America. America knows it shouldn't react, but can't help itself.
With no good reason to do it other than just to do it, Brady has leaned against the prevailing political wind and begun trudging forward.
As far as I can tell, there's nothing in it for him. Given all the people Trump has insulted – essentially, everyone who isn't white and middle-class – it can only hurt Brady's lucrative business as a global pitchman.
And so while Brady risks catastrophic injury every time he gets on the field, this may be his first really brave public act.
What people are trying to figure out now is Brady's end game. Few Americans have a bigger pulpit. If the best quarterback in football history wants to start making waves while he's still playing, they will be tsunamis.
Is his endorsement of Trump anything more than doing a solid for a golf buddy? Are there issues Brady feels strongly about? Is he planning a transition to politics once he retires?
Maybe. Or maybe there is no point to all this. Maybe Brady is doing it because he can, and because it's funny. Go back and watch the video where he says he hopes Trump wins. That's how it looks.
The larger point to sports is its ability to lead change in the wider world. That's an undeniable good. But every once in a while, we need to remind ourselves that putting sports at the absolute centre of our culture – which we have done – is fundamentally ridiculous. Which means we're ridiculous.
Consciously or not, Brady is pointing that out. It may be his most winning performance yet.
Cathal Kelly