Within hours of Mr. Javid’s appointment, the BBC declared that “one advantage” he should have is his background. His parents came to this country from Pakistan. As he told one newspaper, they have something in common with the Windrush families: “It could have been me, my mum or my dad,” he said, “obviously a different part of the world, from South Asia, not the Caribbean, but other than that, similar in almost every way.”

Image Sajid Javid, the new British home secretary. Credit... Andy Rain/European Pressphoto Agency, via Shutterstock

It’s possible that Mr. Javid’s background will grant him more empathy than his predecessors had. But his family history alone doesn’t equal the change that Britain desperately needs when it comes to immigration policy.

The reaction to Mr. Javid’s appointment reveals a serious problem with how many people seem to understand politics. He is the first person of color to lead the Home Office; some cheered him for breaking that barrier. Of course, representation isn’t entirely inconsequential. But for too many, there is a desire to reduce anti-racism and anti-sexism to issues of representation: If we get more women or people of color into positions of power, society will become more equal. You could call this trickle-down equality — and like its economic counterpart, it doesn’t work.

There are two lessons to learn from Mr. Javid’s appointment: The fight against an unjust immigration system does not change with a new home secretary, and if we remain satisfied with representation as the sole means of progress, diversity becomes a shield for a government’s institutionally racist policies.

Hostility to immigration is at the heart of Mrs. May’s government. Before she became prime minister, Mrs. May was the home secretary. In that role, she pledged to get net migration down to the “tens of thousands.” Told it was unworkable, she stubbornly stuck with it. It was and continues to be her mission, in the words of the 2017 Conservative Party manifesto, to “bear down on immigration.”