James Fallows is getting a lot of attention for arguing this week that if the Supreme Court strikes down the Affordable Care Act, it will be a fundamentally illegitmate act on the court’s part. After all, most legal scholars consider the Broccoli Liberty argument to be a joke. This is, no doubt, a critical question; can the Court just do whatever it likes? Is there — and should there be — any constraint?

The key to his argument is the question of democratic norms:

Liberal democracies like ours depend on rules but also on norms — on the assumption that you’ll go so far, but no further, to advance your political ends. The norms imply some loyalty to the system as a whole that outweighs your immediate partisan interest.

I think the concept he’s looking for here is what Mark Tushnet has called “Constitutional Hardball” — in which one party treats the basic rules of the game as limited to what they can get away with, rather than as a combination of laws and norms that everyone abides by. I agree that Republicans on the Court engaged in that in the 2000 election. Other examples? I’d include the mid-decade redistrictings a few years ago, primarily in Texas; the massive expansion of the use of the filibuster in 1993 and then again in 2009; and the impeachment of Bill Clinton.

I think it’s a real problem. There’s really no good reaction to it for the other party; there’s really no choice other than to respond in kind. Ultimately, while we should remember that both norms and rules can be themselves severely, even violently, undemocratic, it’s also probably not possible for a democracy to function if no norms are accepted and all rules are constantly contested.

On the other hand: it’s important to realize that the Supreme Court is inherently and properly a political institution. Elections matter, and that includes the elections that have created the current Court, even though that includes elections stretching back to the 1980s.

There is no hard-and-fast line separating legitimate conduct from illegitimate conduct, either in the courts or in the other branches. On the other hand, a string of actions by the same party over time can add up to something dangerous.

So what do we look for in the health care cases? We want our judges to act like judges: they need to justify their decisions based on something other than just partisan preferences or fig leafs for those preferences. It’s okay — in fact, it’s part of democracy — for judges to have strong points of view, especially ones reflecting the politicians who appointed and confirmed them. So I’d say that a decision that attacks Commerce Clause precedent would be wrong but ultimately a legitimate opinion.

However, a decision based on specious reasoning that sounds a lot like a policy attack on the Affordable Care Act or a partisan attack on Barack Obama would strain legitimacy. In my view, that’s what a Broccoli Liberty decision (based on the supposed tyranny of regulating inactivity) would be. If that’s what the Court does, then we would have a prime example of Constitutional hardball, and another real blow to the Court’s prestige.