Hmm it’s an interesting question. I would say no for two reasons. The US has enough military power to do what they want overtly (see 2026), and I doubt the US could keep something like that quiet for long enough to matter. Surely something like that would have been leaked if anyone knew about it.

I mean yeah that’s kinda the point of sleeper cells.

“So Steve, what do you do for a living?”

“Oh I’m an agent of a foreign country waiting for a signal to strike.”

“Nice, same.”