My point was that Mexico cannot take the southwestern United States unless we give it up. If Americans stand firm in defense of our territory, then there really is no legitimate threat. But, part of standing up is securing our borders and expelling illegals.
There is no way that Americans want or need any the lands our military personnel are in now. If we can both conserve energy and develop our alternatives to oil, then we will be content to have our own country and let others have theirs.