And what makes you think that Mexico has veto power over U.S. sovereignty? Other than GWB, that is.
Mexico is a wealthy, corrupt, third-world disaster, that has kept its own people destitute. Their "internal turmoil" should be their problem; not illegally imported to US.
And what makes you think that Cuba has veto power over U.S. sovereignty?
Cuba shipped over 10,000 aggravated felons (hardcore murderers, rapists, etc)to the US during the Mariel boat lift. Since then, Castro has refused to take back most of them. The US Supreme Court has ruled that such non-admissible aliens must be released.
And that's just one country.