Nine days before the inauguration, the man getting ready to become president held a news conference at Trump Tower in Manhattan and called BuzzFeed “a failing pile of garbage.” Within a matter of hours, BuzzFeed added new merchandise to its online store: a T-shirt emblazoned with “FAILING PILE OF GARBAGE,” a bumper sticker that says “I proudly get my news from a failing pile of garbage” and a “limited edition” BuzzFeed garbage can.

“We are not going to respond to these divisive comments,” BuzzFeed chief executive Jonah Peretti wrote to his staff — but, of course, the merchandise speaks for itself. A shirt emblazoned with an insult is a defiance of that insult; marketing and selling that defiance re-enlists followers in the ongoing exercise of name-calling. (“No, you’re the puppet.”)

Plus, it’s profitable. BuzzFeed made $25,000 on the flash sale (which it says it will donate to charity).

We’ve entered an era when an opponent’s denigration almost instantly becomes a badge of honor. Factions can quickly cluster around the meme of the moment, changing the way we fight each other.

Senate Majority Leader Mitch McConnell probably thought he was getting in the last word in his spat with Sen. Elizabeth Warren during the recent attorney general confirmation hearings when he rationalized cutting her off from the debate by saying, “She was warned. She was given an explanation. Nevertheless, she persisted.” By the next morning, the internet was awash in “she persisted” paraphernalia peddled by everyone from DIY entrepreneurs to major retailers.

At a September fundraiser, Hillary Clinton said that some of Donald Trump’s supporters belonged in a “basket of deplorables.” Trump supporters quickly claimed the term for themselves and re-branded “deplorable” as an honorific.

Trump returned the favor when he called Clinton “such a nasty woman” during the final presidential debate in October. It led to the birth of a whole cottage industry of “nasty woman” merchandise; at least 181 online stores made nearly $2 million off “nasty woman” in the first two months after the debate, according to Shopify.

In the minds of Clinton supporters, “nasty” was no longer a description of behavior but a rallying car for strong womanhood. The term popped up in Twitter bios, nestling between mainstream monikers like “feminist” and “political junkie.”

“Silicon Valley” TV actor Thomas Middleditch, in his Twitter bio, re-appropriated another insult from the campaign: “cuck,” an arch-conservative insult that has come to mean, essentially, a girlie man. (It used to mean a conservative who wasn’t vehemently anti-immigration and/or pro white supremacy, but its meaning has been diluted over the past year by constant use on Twitter.)

It was a small, virtual act of solidarity with women who supported Clinton and/or opposed Trump. One of Middleditch’s followers in Texas took his cue and started selling “cuck” T-shirts, with 75 percent of proceeds reportedly going to the Trevor Project, a nonprofit that works for suicide prevention for LGBT youths.

This sort of reverse branding is nothing new. Tina Fey titled her memoir “Bossypants,” turning a negative term into a mind-set to which readers could aspire. In his comedy act, Jeff Foxworthy turned “redneck” into a term of pride in Southern authenticity. Kate Bolick, a single-and-proud writer, titled her 2015 book “Spinster: Making a Life of One’s Own.”

When accepting an Oscar in 2006, George Clooney said he was “proud to be out of touch,” taking ownership of a common Hollywood critique and redefining it as “forward-thinking” on civil rights, AIDS and other topics that were previously taboo.

History has examples of it, too. In the early 19th century, Ralph Waldo Emerson and his fellow thinkers were mocked as “transcendentalists” because critics considered their rationale “beyond reason and sanity,” according to Jerome Loving’s biography of Walt Whitman. But then the movement decided to embrace the term, and now English majors study transcendentalism as a significant movement in American literature.

What exactly is going on here? Clearly, the idea is that one way to stop trolls is to troll yourself first — to embrace, re-appropriate and declaw the word, even before it can be used against you.

Or put another way: If the enemy of my enemy is my friend, then an insult from my enemy is a compliment.

Take “Obamacare.” Yes, it started off as mocking term, popularized by the GOP to tie the president’s name to legislation it viewed as disastrous. Next thing you knew, Democrats were using the taunt as friendly shorthand for the Affordable Care Act.

“I like the term,” Obama once said. “Because I do care.”