So What's the Law That Judges and Government Officials Should Follow?

In the wake of the Ten Commandments cases, how should an honest lower court judge -- or government official -- apply to decide whether some government speech that has a religious flavor violates (or would violate) the Establishment Clause?

(1) Apply the endorsement test, on the theory that the majority in Allegheny v. ACLU endorsed it, and that it therefore represents the most recent majority view on the subject.

(2) Determine whether the government speech is likely to prove religiously divisive, as Justice Breyer's controlling opinion in Van Orden v. Texas suggests -- or, if the issue is whether to remove a display, whether the removal of the display is likely to prove more or less divisive than retaining the display.

(3) Apply "legal judgment," for which there can be "no test-related substitute," also following Justice Breyer.

(4) Something else.

I'm genuinely curious what the legal answer should be here. After all, many government officials (maybe not all, but many) genuinely want to follow the law. They may even realize that they can get sued (or, if they're judges, that their decisions will be appealed) no matter what they do, and that they can't be sure how the case will come out. But they'd like to do what the law requires. What, though, is the law now, following the splintered opinion in Van Orden?

I'd love to see some serious responses (rather than jokes, rants, or fulminations). Also, let's avoid in the comments to this post express criticisms of the Supreme Court's decision or its broader caselaw: Rather, let's see what the caselaw requires, and then each of us can use that as a means of evaluating that caselaw.