I don't doubt that Bush believes he has saved more American lives when the overall economic impact of illegal immigration is taken into account than the few thousand which have been lost because of criminal action by illegals. No doubt that he believes he has helped stave off a Communist revolution in Mexico that might have killed millions. No doubt that he believes he is denying Hugo Chavez (and by extension, China) an expanded role in the Western Hemisphere.
But since he seems to have decided he can't comment publicly on these aspects of the issue - particularly on the way illegals are propping up our house-of-cards economy at the moment - he has apparently decided to take the short-term political hit in the hope that history will prove him right, much as he did to shield Putin from the repurcussions of Putin's decision to help Iraq move its WMD's to Syria before the war.
Bush isn't a villain - but he's too much of an "ends justify the means" guy to be a hero, either.
You don’t destroy America to prop up another country. Illegal immigration has wrecked hundreds of towns all across America and it is getting worse every day.