Bright Lines and Reasonable Persons

So, the Supreme Court is hearing another 10 Commandments case today - this is about the 10 Commandments on display in courthouses. IMO, such a display, if the text of the commandments is given prominence, constitutes an establishment of religion... which, of course, is prohibited by the first amendment to the Constitution.

Cases like this tend to be decided 5-4 with Sandra Day O'Connor the swing vote. She likes to apply this test: if a reasonable person would construe a particular state-sponsored display of the 10 Commandments as an expression of religion, then that display constitutes an establishment of religion.

I can't really argue with that. It's a pretty good principle.

But I heard a lawyer on the radio today complaining that O'Connor's principle doesn't draw a clear bright line.... This may be because there are no lawyers who are also reasonable persons :o)