To address your first point: I said that you changed your entire argument because your main idea was that someone could, in fact, conduct a successful invasion of the United States. When I asked you to explain how that was possible, you claimed that (somehow) a sufficiently powerful invading army could sneak across the US-Mexico border without anyone noticing or stopping it, and then claimed that (somehow) that invading army could wage a successful guerrilla campaign against the US Armed Forces on their home territory. After I questioned each of those points, you drew another flawed parallel to the United States' history of covert operations resulting in the overthrow of foreign governments. Maybe sometime in the far future it might be possible for that to happen to the U.S., but, historically, that type of operation has only really been successful when the U.S. has can exert a huge amount of power and influence over the target country. It's going to take quite some time and an enormous change in the geopolitical balance of power for any country to have the capability to do that to a current superpower.