The uniform did what uniforms are designed to do.

When Lt. Col. Alexander Vindman appeared before the House Intelligence Committee, his striking presence in his serviceable eyeglasses and his military uniform exuded authority, ferocity and patriotism. As one of the Democratic committee members noted admiringly, Vindman was wearing a Purple Heart on his uniform. He also had a Combat Infantry Badge pinned on the left side of his chest, indicating he’d been involved in active ground combat. For civilian viewers, it was helpful to understand the meanings of some of the insignia on his jacket. But even without the details, anyone looking at the vast collage of medals spread across his chest could understand the story they told: that Vindman is one of the many dedicated individuals who choose to stand guard so that others might sleep easily.

Military uniforms command respect. They’re also intimidating. Uniforms are a testament to chains of command, order and service. When worn by a group of men and women, they create a visual wall, an impenetrable and emotionless barrier.

But from the moment Vindman took his place behind the witness table, it was clear he would not be an emotionless presence. He would be a humane one. And that made his decision to appear in his Army service uniform particularly affecting.

As he waited behind the wooden table for the other witness of the morning, Jennifer Williams, a Russia adviser to Vice President Pence, Vindman looked around the crowded room in the Longworth House Office Building, taking in the spectacle. Often, witnesses stand stiffly and stare into the middle distance as photographers click away. But Vindman’s body language expressed curiosity — and perhaps a bit of nervous energy. He peered up at the ceiling. He looked behind him to where his twin brother, in a dark business suit and red tie, was sitting. (It was a bit like seeing an alternative Vindman — the officer as Everyman.) Vindman adjusted his glasses. He absorbed the moment, and he endured it.

When Williams arrived, Vindman reached over to pull out her chair. It was a polite, old-fashioned gesture. It was touching. Williams could, of course, manage her own chair, and perhaps she would rather he had allowed her that. But on the face of it, Vindman’s pulling out the chair for his fellow witness was an act of kindness, a particular human instinct that hinted at the person inside the uniform. It was a gesture of civility and humility at the beginning of a hearing in which focused interrogation was soon to be overtaken by jousting, interrupting, pandering and Jim Jordan’s bulldogging. (Does the representative from Ohio have a question for Lt. Col. Vindman? No. He is quite content to stare over his reading glasses, shout at the witness and spar with himself.)

Vindman reminded observers that a military uniform is not only an emblem of a warrior; it is also a mark of an honorable individual.

The witness’s uniform became a point of conversation throughout the hearing. When Rep. Devin Nunes (R-Calif.) addressed Vindman as “Mister,” Vindman corrected him, politely but firmly: “Ranking member, it’s Lt. Col. Vindman.” The witness was demanding respect for himself as well as the standards and practices of the military in which he served.

Rep. Chris Stewart (R-Utah) suggested that correcting Nunes had been a pompous swipe. He wondered why Vindman was wearing his dress uniform. Why wasn’t he wearing a suit? And to underscore his standing to ask Vindman such questions, Stewart pointed to a pair of wings on the lapel of his own suit jacket, noting that they belonged to his father, who served in the military. This was just one example of the self-reflective blah-blah-blah that infected Tuesday’s first hearing: the congressmen who knew a thing or two about the military, or about being the child of immigrants, or being an identical twin.

Stewart implied that Vindman was exploiting his uniform to make a point, that he was relying on it as a cheap visual retort to those who would question his statements. Vindman said he’d chosen to wear his uniform and to correct Nunes in part because his service and patriotism had been attacked on social media. His attire was a retort. For Vindman, who had been wounded in Iraq, his wearing the uniform had cost him deeply.

Stewart was right to fear the uniform. He was right to be bothered by its potential to add substance to Vindman’s words. But the impact of what the witness wore didn’t come solely from the golden epaulets and shiny buttons and medals. The uniform carried weight because Vindman did not disappear into it. He was not an automaton. He was not stoic.

He was a son who reassured his worried father in his opening statement: “Do not worry. I will be fine for telling the truth.” He was a military officer who called himself “never partisan.” And he was a vulnerable human who began the morning with a powerfully kind gesture to the only other person in the room who really knew how he was feeling.

Read more on politics and fashion by Robin Givhan: