It might happen if it were intentional. Internal security sabotage for the benefit of an enemy nation for example.

Given the scale of what's going on in the world right now, with huge powers conflicting, it would be far more surprising with the gigantic size of the US Government if there weren't internal actors (on the payroll of foreign enemies) aggressively attempting to do this. It was common in the past, for example during the Cold War (Soviet infiltration of the US Government, and persistent attempts at), you can pretty well bet it's still a common problem.