Other the European racism what was the problem? The US could use a few million people who work hard and believe in democracy.

Mexicans you mean? People from Syria can not be simply compared to people from Mexico, there is nothing racist about Europe's hesitance to accept more Islamic immigrants. To start with a significant part of them most definitely does not believe in the sort of democracy we maintain.

We can cut off illegal immigration by fixing the problem at the source. Illegal immigrants in many cases are fleeing oppressive regimes and evil dictatorships. We have the largest military on Earth. Let’s use it to help overthrow evil dictatorships in countries like Venezuela and combat drug gangs in Columbia. Let’s give these people free governments. Then they will have no reason to flee and try to emigrate illegally to the United States.

If you could defeat a drug gang with military power, then Mexico would have done it by now.