Protecting North American security makes each country safer. Having Canada, for example, be part of our NMD system benefits us both.
It's not an either/or situation. We need to protect our own borders at the border and we need to jointly protect North America.
I don't know why that's controversial. Let's work on both.
American citizens should not be paying for Mexico's southern border.
What American citizens would like, however, is securing America's borders, north and south. This is not being done.