Peace Cross Puzzlement

The Maryland Bladensburg Cross was allowed to stand. That's the easy part. The hard part is what precisely prevented the Court--for the second time in as many Establishment Clause cases involving these kinds of issues (see also Town of Greece)--from cobbling together a majority opinion repudiating Lemon/endorsement and offering a new approach, even one limited to religious displays. Instead, we got

• a plurality opinion (joined by Justice Breyer) with lots of extremely critical commentary about Lemon/endorsement, but that does not overrule Lemon/endorsement even in this narrow area;
• one concurrence that would have overruled Lemon/endorsement;
• one concurrence that preserves Lemon/endorsement;
• 4-6 votes for a history and tradition approach whose contours vary significantly depending on the justice;
• two opinions concurring in the judgment that would have overruled Lemon/endorsement;
• a dissent by Justice Ginsburg joined by Justice Sotomayor.

The puzzle: what prevented a majority from overruling Lemon/endorsement even in this specific area? Does Lemon/endorsement continue to apply in this area where the display is new and/or there is (lots of?) evidence of discriminatory motive? I find it difficult to understand how the extremely critical comments about Lemon/endorsement that four justices put their name to in the plurality, plus the views of another two justices that were ready to overrule Lemon/endorsement altogether, do not add up to some kind of actual overruling. Justice Kagan could certainly have written a concurrence in the judgment. Not to be, I'm afraid. Still, I'll have more to say about the 4-6 votes for some variety or other of a history/tradition approach soon.