How much of an impact does a fashion statement have the second (or third) time around?

Last year at the State of the Union address, a majority of the women of the Democratic Congressional Caucus wore white — white suits, white dresses, white shirts, white jumpsuits — as a nod to the suffragists, to women’s’ rights, as a silent riposte to President Trump and as a message to the electorate about their own unity. This year, many of them did it again.

On the podium, Speaker Nancy Pelosi wore a white pantsuit with her dagger-like Speaker’s Mace pin on her lapel. Before the event, the women had posed en masse:

In the House of Representatives chamber, they sat as a visible block: an island of white in a sea of largely dark suits and the occasional bright blue or red jacket.

It was not as startling or as striking as it was last time — at this point, post-Hillary Clinton candidacy, the white suit has become a political uniform of its own, on par with Mr. Trump’s navy suit and red tie (which he also wore Tuesday evening). The color’s meaning, and signifier as a form of female empowerment and protest at major public moments, has been codified. We are even starting to expect it.

But that doesn’t mean it was not an effective tactic. In a moment where the only person speaking is the president, but millions outside the chamber are watching, it allowed those members of Congress to have a say. The clothes become a proxy for the point.

In the context of the impeachment drama that has been playing out and is expected to come to a close on Wednesday, it was a reminder: That battle may be almost over, but the fight is still on.

Clothing has always played an outsize role in the theater of this administration. Mr. Trump responds to the concept of dressing the part, be it the part of a military general, a spokesperson (Sean Spicer missed that memo during his time as press secretary and communications director in the executive branch), or part of the opposition. After all, it’s an easy signifier; something almost anyone can read.

The irony is the one person who seems reluctant to avail herself of this tool is the first lady.

Melania Trump long ago refused to engage in any consistent way with the game of diplomatic dressing; refused to imbue her wardrobe with any meaning other than “clothes I like” (well, except for that confusing “I Really Don’t Care, Do U” coat moment); refused to hew to the tradition of supporting American industry by wearing American designers. Even at such freighted moments as the State of the Union, when there’s no question the camera will keep panning up to her balcony box, where she sits smiling (sort of) and waving, a silent image.

If there was ever a time to engage with that sort of performative dress, it would be the State of the Union; ever a time to support her husband by sartorially waving her (and thus his) patriotism in the face of those who say he has suborned it, this was it.

But nope.

Though Mrs. Trump dipped a toe in the waters for her husband’s first major Congressional address, wearing a sparkling suit by Michael Kors, at the following State of the Union came a suit from Christian Dior, then a coatdress by Burberry, and on Tuesday evening, Mrs. Trump wore a dark navy suit from Dolce & Gabbana.

The Italian label is a staple of her wardrobe — remember the $51,500 floral coat she wore to the Group of 7 meeting in Sicily on her first foreign tour? — but lately it has been in the spotlight for being canceled in China after seemingly offending the entire country with an ad campaign.

Maybe Mrs. Trump wasn’t aware of its blunders, or that before that the designers had also been embroiled in controversies over fat-shaming and same-sex families. Maybe she didn’t care that those watching might construe her choice to wear Dolce at such a high-profile event as tacit support — and that indeed, those pictures of her can be used as exactly that sort of evidence forevermore — because she just likes Dolce’s clothes (certainly the suit, which was buttoned-up to the throat with two military rows of buttons, strictly tailored, was very much in her style comfort zone).

If people want to read the wrong message into what she wears, that’s their problem. She always looks polished and appropriate. No question. Maybe that is how she defines her duty; her message is there’s no message.

But when so many others in the room are using clothing as conversation — and signaling their intent well in advance — and when her role is as the symbolic partner of the nation, is that really an option?