I think that the Border Patrol ought to post huge billboards before the north-bound border crossings that say "Please Be Advised: Anticipate A Re-entry Delay Of 5 To 24 Hours - All Vehicles Will Be Thoroughly Inspected To Insure Against Terrorist Activity"
Perhaps most Americans would stay home, perhaps the Cans would learn to appreciate the ability to come and go to America, and finally the Can government might learn the value of being a trusted ally of America or be replaced.