Why no, I'm vehemently against it.
We should use massive military firepower, routine and mass deportations if necessary, and ruthless assertion of American political and cultural institutions on those who are admitted legally.
If we are weak enough to let them take over, then...they will.
If the Canadian Communists are strong enough to resist us, then...they will.
It's the way the West Was Won.
In less than 100 years, Hispanics will be the majority population segment and will probably be running the country and the military. So you better hope that there's NOT going to be mass deportations and use of "military firepower" and "ruthless assertion" of dominant cultural values, or your great, great grandkids will either be playing in a mariachi band or deported back to Muslim Euroland. :D