What effect will the Supreme Court decision Monday on Arizona’s immigration law have on the 2012 election? Chris Cillizza argued that it was bad for Mitt Romney, because he would rather not talk about immigration at all (an argument certainly confirmed by today’s greatest transcript, in which the campaign ducks substantive comment on the decision). Jennifer Rubin, on the other hand, believes it was good for Romney, because it tends to take the Arizona law off the table as a campaign issue.

I’ll say now what I almost certainly will say after the health-care ruling, due now for Thursday: Supreme Court rulings such as this one almost never have much effect on the next election. This one is almost certainly no exception.

There are basically three ways that a court ruling in June (or earlier) could affect the vote in November, and they’re all extremely unlikely to happen in any great numbers.

One is about the issue itself. But how would that work? Suppose you supported Barack Obama’s position on the Arizona law, and were also an undecided voter. How would the Supreme Court’s action — any possible action — logically get you to change your vote? Would Obama no longer be able to talk about immigration, regardless of what the court did? Of course not. Would you probably change your mind and decide you opposed Obama’s position now that the court weighed in? Virtually no one thinks like that. Would you believe the issue is settled, and no longer relevant to the election? Highly unlikely; Supreme Court cases rarely if ever fully settle an issue.

A second possibility is that a Supreme Court victory or defeat could change the general story of the administration. Those who believe in “narrative” theories of presidential elections no doubt embrace this theory, but there’s not much evidence to support them.

And then there’s one other possibility: that high-profile Supreme Court cases could make the court itself a larger issue in the election. That’s certainly possible, but there just isn’t very much history to support it. Generally, as important as process and procedure question may be, voters just don’t care about them very much, and the court is ultimately a process issue, rather than a substantive one, at least in electoral terms. That is, a candidate is going to get a lot more mileage from saying “vote for me because of immigration” than “vote for me because I’ll appoint someone to the court who will uphold the right immigration policy.”

Supreme Court decisions are in fact terribly important substantively. And in the long run, it’s possible that for example this Arizona decision could wind up affecting the long-term loyalties of Latino voters, including how many there will be and how likely it is that their political identify is found in ethnic and immigration politics. But for better or worse, it just isn’t going to make much difference in November.