Marcia Clark Says O.J. Simpson 'Doesn't Seem to Be in Control'

Marcia Clark's studied O.J. Simpson as closely as anyone on the planet ... so, it means something when she says his post-prison behavior seems totally out of control.

We got the famed O.J. prosecutor at LAX Friday and asked her about the story TMZ broke -- Simpson getting booted and banned from the Cosmopolitan Hotel in Vegas.

Marcia's heard the news, and seems baffled by the choices her nemesis continues to make. Will it be enough to get his ass incarcerated again?