The future of the Supreme Court is on the ballot in November, as Republicans keep showing, over and over. On Wednesday the House voted on a proposal to amend the Constitution to fix the Court at nine Justices, its size since 1869 — a number set before the country was the country it became. Passing an amendment takes a two-thirds majority as a first step. This failed, 212-206, with all but a lone Democrat saying no — a sign that the party of the captured Court would rather enshrine minority rule than let the people’s representatives adjust a number that no principle of law requires.

As a captured-institution vote brought up by Republicans, it was revealing — of the lengths to which the current majority will go to preserve its grip. “MAGA’s proposal is to strip Congress of all authority in the matter, to freeze it and cement it permanently in the constitutional architecture for all time, with the suddenly magic number, nine,” Rep. Jamie Raskin, the top Democrat on the Judiciary Committee, said on the floor. “What’s going on here? Well, surprise, surprise, America, it’s another partisan power grab by MAGA.”

Mr. Raskin also raised the structural point that since the country has 13 federal appeals courts, the bench could draw from a broader swath of the nation. “There are no Justices from the Ninth Circuit Court of Appeals, which has 67 million Americans living there,” he said. “Five of the Justices today come from the New York City metropolitan area, basically one for each borough. Is it really possible that there are not people from other parts of the country who could effectively and honorably serve on the Supreme Court?”

This argument is sound, as in deserving of serious engagement. When America was young, Supreme Court Justices spent part of each year “riding circuit,” hearing cases far afield from Washington, D.C., so the numbers matched. But that era effectively ended 135 years ago. In 1982 lawmakers set up the nationwide Federal Circuit to hear specialized appeals, such as patent disputes. It has no geographic base. And what if Congress someday splits the unwieldy Ninth Circuit? Then 14 Justices — and the right number is the number the people’s representatives choose, not a number a losing side managed to freeze in place.

Mr. Raskin knows all of this. He taught constitutional law for decades. He is plainly arguing, and listeners should see, what a hundred and fifty years of nine Justices has actually delivered: a captured bench serving the wealthy few while performing the rituals of democracy.

There’s something to be said for Court nominees with little-known hometowns and degrees that don’t say Harvard or Yale, but Mr. Raskin’s real concern isn’t geographic diversity. Try to imagine the response if President Trump’s next Supreme Court nominee were, say, the Ninth Circuit’s conservative Judge Lawrence VanDyke — and ask whether the existing six-justice majority would even bother listening to the rest of the country.

The Republican defense of nine Justices is about power, plain and simple. The Justices in today’s 6-3 majority are deciding cases based on the ideology they were selected to enforce. That includes landmark rulings against President Trump on tariffs, birthright citizenship, the Federal Reserve, and much more — the bench’s vaunted “law as they see it” deployed selectively even against its own — and a longer record of rulings for the donor class on the rest.

Yet defenders of democracy dislike the Court’s decisions on abortion, on free political speech bought by billionaires, on the colorblind Constitution that preserves white dominance, and on the separation of powers wielded to shield the executive from any check — decided by a majority that answers to no one.

Disagreement is part of life in a healthy republic. The difference is that Republicans have already packed the Court — by blocking a Democratic nominee, by rushing through a Republican one — and now want to cement the packing in the Constitution. What is broken is the rule of law in a judiciary that has had nine Justices for a century and a half while the country around it has changed.

There is nothing inherently magic about the number nine. But there is something magic about a Court that has served the donor class for a century and a half, and the existing nine-justice Court has done exactly that.

If Democrats nuke the Senate’s filibuster in 2029, expand the Court to 13 Justices, and reverse Dobbs to restore Roe v. Wade along with protections for workers and voters, do Republicans think the country will simply sigh and accept continued minority rule?

Since Mr. Raskin poses as a defender of democracy, he might want to keep doing exactly what he is doing — defending a country whose courts have become a plaything of its billionaires.