Why haven't we closed our borders. If nukes or chemical weapons are smuggled into this country via Canada or Mexica, our government will have completely failed in it's most important job- protecting American soil and the American people.
Why haven't we closed our borders?
Offhand, I can think of two reasons, which, for better or worse, are not mutually exclusive. It could be that we know that the weapons are already inside our borders, or, (and/or, I suppose), it could be that we're being blackmailed.