Since I can't know the exact contents of the lawsuit I can't give a straight answer to that, Boyd.
But as a general response, yes, I think it may be justified.
The FCC is the controller of what can and cannot be used in the various bands of the radio frequency spectrum. That is, it defines and approves what you can do in various bands. So it knew in advance and agreed, at least in principle, to LTE use in that band by the simple act of selling licenses to LightSquared for that use. A company like LightSquared would never have begun serious product development if the FCC had not sold them the necessary licenses.
So it's not out of the question that LightSquared may have a good legal basis to sue the FCC for some form of relief. In this case it could easily be construed that the FCC used them, intentionally or through negligence, to do the research to determine feasibility of LTE in this band.
The basis for this would be that many experts in the field were hollering at the FCC about interference issues almost the instant LightSquared announced their product development plans.
So, it's not like the FCC was not warned immediately after the sale of the spectrum. And, further, it should be really easy to demonstrate that the FCC should have been able to see this themselves without having to have it shoved in their faces in this fashion.
And, finally, at worst the FCC could easily be seen as culpable by allowing the development to go on as long as it did before finally pulling the plug, given that all of the necessary evidence to stop it was in front of them much earlier.
Please understand that I'm not trying to be an apologist for LightSquared. I don't believe there is any grounds for allowing them to continue to try to use their licenses if there is any chance at all of GPS being screwed up.
I'm simply saying that the FCC pretty much screwed the pooch by selling licenses to use spectrum so close to the GPS frequencies without doing a lot more homework. And then made it worse by not taking the concerns of experts seriously enough, soon enough. So it would not be unreasonable to ask the FCC to, for instance, buy those licenses back. And maybe pay LightSquared something for being the R&D guinea pigs for the applied research that the FCC might have otherwise contracted to someone BEFORE selling those licenses.