Given this administration's willingness to trample on language, I assumed it was a recent bastardization.

I thought this could be the case as well, or that he just messed up, OR that he really had some weird concept going on there. I'm so glad you posted this because really I never heard "existential" used this way. I'd been pondering his use for two days. I don't like it, existential used that way. No, don't like it. :)