I can't define a real leader since we've not had one in my lifetime although a couple Presidents have come close. Anyway, we have our military in numerous countries guarding borders and sections of certain regions to PREVENT hostile action. These policing duties have increased steadily over the years and if our government can spend billions of our dollars to assist UN and NATO initiatives then why the hell can't they do the same to protect our borders from rapists, murderers, Al Quaeda and who knows what other vermin. What's your solution..wait until a Border Patrol agent is murdered or a Ariz. rancher is ruined by illegals killing parts of his herd?
Anyway, we have our military in numerous countries guarding borders and sections of certain regions to PREVENT hostile action.Where it's worked: the old inter-German border region, Kosovo (stopping the VJ from bringing their tanks back into the area), and Korea (at least as far as stopping massed assaults by armored and mechanized infantry armies.)
Where it hasn't worked: Kosovo (stopping the KLA), Korea (stopping saboteurs and spies from crossing the DMZ), Vietnam.
Which set of situations is closer to the situation on the US-Mexican border?