The US Supreme Court denied certiorari in Mount Soledad Memorial Association v. Trunk, which lets stand a 9th Circuit ruling that the cross was unconstitutional.  While some have claimed this was a victory for church/state separation, the ruling was actually more nuanced — and not focused on Constitutionality at all: 

The Court of Appeals remanded the case to the District Court to fashion an appropriate remedy, and, in doing so, the Court of Appeals emphasized that its decision “d[id] not mean that the Memorial could not be modified to pass constitutional muster [or] that no cross can be part of [the Memorial].”…

In other words, the response to the order from the appeals court hasn’t been finalized, so the Federal government’s response is as yet unknown.  For the record, the Justice Department has been defending the cross.

A response to the 9th Circuit’s order will occur, which will likely involve a land transfer, and the case will likely work its way to the Supreme Court again.

With reference to the Religion Clause.