President Biden last week announced the formation of a bipartisan commission to study various reforms to the Supreme Court. Chief among the possibilities, and seized upon by conservatives as the entire reason for the exercise, is the idea of increasing the number of justices to twelve or even fifteen, pejoratively referred to as “packing” the Court.

It’s fair to say that the main impetus for such a move would be to dilute or reverse the current conservative majority on the Court, engineered by Mitch McConnell and the Federalist Society through their willing lackey, Donald Trump. Elections famously have consequences, and one of the most lasting and easily foreseen  consequences of Trump’s win in 2016 was the reshaping of the federal judiciary in a much more conservative mold, starting with the composition of the Supreme Court. The final blow to Democrats was Ruth Bader Ginsberg’s death and the rush, just before the election, to confirm Amy Coney Barrett, a hypocritical bookend to Republican Senators’ refusal to even conduct hearings on Obama’s nomination of Merrick Garland to the Court more than a year before the previous national election.

This is the sort of thing over which otherwise sober politicians begin to plot vengeance, and Biden’s commission has at least a whiff of that about it. It’s the Democrats’ version of the voting “reform” (or “suppression” – take your pick) legislation currently steamrolling through various Republican-dominated statehouses: take an established governmental institution that doesn’t work for you the way it used to, and “reform” it in a way that restores its former bias in your favor. It’s one of the most persistent themes in the history of American politics.

But if we strive for some objectivity about it, does the Supreme Court need to be reformed, and if so, how? What are its real deficiencies apart from the fact that it may not favor liberals’ policy interests the way it once did?

The phrase “Court-packing” was coined during President Franklin Roosevelt’s attempt to overcome a Supreme Court majority that, despite his landslide reelection in 1936, declared key parts of his New Deal unconstitutional. His proposal to increase the number of justices to fifteen was opposed by Roosevelt’s own party, and was rendered moot when two sitting justices, in the famous “switch in time that saved nine,” upheld the Social Security Act.

But the story of how many justices sit on the Supreme Court begins much earlier.

Surprisingly, our Constitution, which went so far as to specify what fraction of a slave counted as a person in determining how many representatives a state would have in Congress, says nothing about how many justices should compose the Supreme Court, and instead delegated to Congress how it would be organized.

In the Judiciary Act of 1789, Congress set the number of justices at a mere six. Thereafter, in response to the growth of the country and the later-abolished requirement that Supreme Court justices “ride circuit” in the district courts, the number of justices was gradually increased to ten. In 1866, in a political move that might be called “Court-unpacking,” Congress passed a law requiring that retiring justices not be replaced until their number dropped to seven. But before that attrition was completed, Congress in 1869 fixed the Supreme Court headcount at nine, where it has remained ever since.

So the first point to bear in mind is that the authority to change the size of the Supreme Court lies, as it always has, with Congress, and not with any presidential commission, or any president. Second, there’s nothing remotely insidious, much less unconstitutional, about making such a change. The number of justices has fluctuated more than half a dozen times in our nation’s history, often for baldly political reasons.

One rationale for increasing the number of justices would be to allow for a balance of factions: five Republican appointees, five Democrat appointees, and five selected by the first ten. While this sort of blunt political head-counting has a crudely egalitarian appeal, its overt reference to party would tend to institutionalize the politicization of the Court as a kind of super-legislature.

But there is one good reason to increase the size of the Court that has nothing to do with influencing policy outcomes: to implement term limits for Supreme Court justices.

Unless they voluntarily retire, the Court’s justices currently serve for life (though the Constitution only states that they may serve “during good behaviour”) and thus can exert their ideological influence on a wide range of critical issues for a generation or more, perpetually unaccountable to the people. This may have made sense at the founding of the republic, when a lifetime meant a handful of decades and monarchs were in the habit of replacing jurists they didn’t like. But today it’s commonplace for justices to live well into their eighties, often struggling with health issues while avoiding retirement until the politics of replacing them suits their preferences – or until time runs out, as it did for Ruth Bader Ginsberg.

Term limits (say, eighteen years) for Supreme Court justices would lessen the intense partisanship that inevitably surrounds appointments to a lifetime position while ensuring a predictable freshening of the intellectual lifeblood of the Court. After their term, justices would achieve “senior” status and, if they wished to continue to serve, could assume a lower court judgeship, thus meeting the constitutional standard for their tenure.

But an orderly transition to term limits would require staggered appointments of term-limited justices while the current justices served out their unlimited terms, temporarily increasing the size of the Court during the transition period until all of the justices were on term limits.

Biden should withhold his endorsement of any plan to pack the Court purely to achieve preconceived policy outcomes. That’s the job of the legislature, not the courts. But the number of Supreme Court seats is not written in stone, nor in the Constitution, and the nation deserves a less partisan and more predictable process of filling them. Limiting the justices’ terms would be a truly bipartisan reform that would logically require an increase in their number.