JMO, islamic terrorists can blend in much easier in Canada, where they have large communites(ala the UK) and a govt. that is so PC, they won't do anything about it.
That's what gets lost in these debates on FR, the large well establshed islamic extremeist communites in the country to the north of the US shares a 3,000 mile border with.
But the net result of such a scenario would be the same, for BOTH borders. It would result in a new immigration policy---probably overly restrictive, but that's life.
Your right on one aspect Dane, but you miss another. Sure, we need equal vigilance on both borders, but if you want to scarify a government, take a closer look at Mexico's without your blinders; maybe you'll notice the corruption among Mexican officials - both in law enforcement and government, something not as widely reputed among our Northern neighbor.
Also, it isn't Canada running her poorer citizens across her borders in search for a better life because of a failed socialist system.
Canada and Mexico are in no way comparable.