As Mr. Plank of Under Armour recently discovered, the biggest risk in the newly politicized marketing space is in offending the core consumers who drive the cultural conversation around its wares. When Mr. Plank called Mr. Trump “an asset,” it didn’t sit well with brand ambassadors like Stephen Curry and Misty Copeland, or the customers they’re paid to attract. The conflict caused a media sensation, and the stars prevailed: Mr. Plank walked back his Trump endorsement in a full-page ad in The Baltimore Sun.

Companies may be drawn to the resistance out of obligation or opportunity, but that doesn’t mean they’re necessarily assets to the cause.

Political slogans that ricochet across the internet can be flattened once they’re co-opted. In a now-infamous February exchange, Mitch McConnell, the Senate majority leader, cut off Senator Elizabeth Warren for reading a letter by Coretta Scott King in a debate over Jeff Sessions. Mr. McConnell’s rebuke — “nevertheless, she persisted” — went viral. Three days later, Reebok’s website was offering a T-shirt featuring the phrase. Ms. Warren’s political argument — that Mr. Sessions was not qualified to be attorney general because of a history of racism — was repurposed as an inspirational workout slogan.

By the time I found the merchandise, the shirt was sold out. But the corporate messaging remained: “As a women’s-first brand, we stand behind the Women’s March and believe we have the resources and platform to contribute to the cause in a meaningful way.” Reebok invited me to submit an email address to “stay updated on all our women’s stories.” Instead I received a 15-percent-off coupon for my next order.

And so political outrage is distilled into slogans that get printed on T-shirts that direct our attention away from politics and send us clicking through the virtual racks of a multinational corporation.

All of this political branding came to a head during the recent International Women’s Day, when feminist organizations, including leaders of the Women’s March, called for women to strike to raise awareness for women’s labor causes. On this “Day Without a Woman,” women were urged to take the day off from work, avoid shopping and to wear red in solidarity. A branding bonanza ensued. On Instagram, Morton Salt’s girl mascot exited the logo: “Changing into something red,” the caption explained. (Morton Salt is a subsidiary of K+S, a German chemical company whose top executives are all men.) The sportswear designer Tory Burch also chose the day to start her new “Embrace Ambition” campaign, a kind of “Lean In” rehash but with more celebrity endorsements and greater integration with Tory Burch products. And United Talent Agency, a news release told me, observed the day “by holding off-site events for its female employees in its offices in New York, Los Angeles and Toronto.”