Help understanding Justice Breyer's “If A can do it, B can do it."

Question

The New York Times just published an interview with US Supreme Court Justice Stephen G. Breyer titled Justice Breyer on Retirement and the Role of Politics at the Supreme Court in which there is a quote I do not understand on the political topic of expanding the court:

Justice Breyer said he was wary of efforts to increase the size of the court, saying it could erode public trust in it by sending the message that the court is at its core a political institution and result in a tit-for-tat race to the bottom.

“Think twice, at least,” he said of the proposal. “If A can do it, B can do it. And what are you going to have when you have A and B doing it?”

Such a judicial arms race, the justice said, could undercut public faith in the court and imperil the rule of law. “Nobody really knows, but there’s a risk, and how big a risk do you want to take?” he said.

“Why do we care about the rule of law?” Justice Breyer added. “Because the law is one weapon — not the only weapon — but one weapon against tyranny, autocracy, irrationality.”

The fact that the NYTimes does not elaborate or otherwise provide background information about the quote, and neither does Politico's Stephen Breyer says he's still mulling retirement suggests to me that the writers and editors associated with these articles felt the quote stands well on its own, without any need for explanation or elaboration.

And of course, a seasons Supreme Court Justice has some familiarity with speaking clearly and routinely articulating their thinking.

But I haven't a clue what “If A can do it, B can do it. And what are you going to have when you have A and B doing it?” could possibly mean. This is not unusual, sometimes I have problems parsing sentences that others don't.

Question: What does Justice Breyer's “If A can do it, B can do it." mean in the context of the possibility of expanding the US Supreme Court?

Answer 1

A and B are the Democratic and Republican parties. If one party does it, then since the power to do so isn't based in their party, then the other party can do the same. So if Democrats make a 13+ member liberal majority court, then as soon as Republicans control Congress and the Whitehouse they can make a 15+ member conservative majority court. The reason we don't see this constantly happening is that politicians long ago figured out this sort of back-and-forth could become eternal, and so while they have the constitutional power to do so Congress has generally stayed away from partisan inspired changes to the number of Justices. And these days even a non-partisan inspired one would almost surely be spun as a partisan one by the minority party.

Answer 2

By "A" Breyer means the Democratic Party, and by "B" he means the Republican Party. So:

“If A can do it, B can do it. And what are you going to have when you have A and B doing it?”

...means:

"If a majority Democratic Congress can expand the court for political rebalancing, then later on a majority Republican Congress can do it, (or undo it), too."

---

There seems to be an underlying assumption of Breyer's argument that the process hasn't yet commenced. To the contrary, there's a body of criticism that holds that B in effect already did it, (or accomplished the same effect), by damming up the normal flow of prospective Justices so that the balance of the SC no longer reflects the overall balance of the mainstream public mind. If that's true, then the Q. should be, if B did it, (and the SC is now abnormally partisan), should A:

1. Try to undo it so that the SC reflects the national balance.

2. Reverse it so that the SC becomes abnormally partisan with preference to A.

3. Do nothing, and let the SC remain abnormally partisan with preference to B.

Readers interested in Game Theory may recognize the the optimal strategy depends on what B is likely to do:

1. If as though waking from a fever B seems likely to recover its former sober appreciation of the impact of a balanced Court upon national morale, then A should attempt to undo the imbalance, and the Court and Congress would be as it was before.

2. If B seems likely to remain incorrigibly and peremptorily partisan, then A's optimal strategy is Tit for Tat as a self defensive measure. So if B does it, A does it -- but if B does not do it, A doesn't do it either.

   If after a few cycles that doesn't help, then the Court's former admired long term stability would be no more, but with Tit for Tat there might at least be a kind of oscillating stability, where alternating partisan majority Congresses would always have complimentary partisan Courts, perhaps making the Court a kind of generational franchisee of partisan Congresses.

3. Or if B seems in the long term to have become irrational or gone mad, the best option for A might be to consider doing nothing -- the problem may fix itself. The Court would then be an exclusive franchisee of a partisan faction -- to the extent that the faction is irrational, its decisions, and its franchisee Court's decisions, would likely become nationally harmful, which eventually would make B and B's Court both very unpopular.