How hard is it to slip undetected across the U.S.-Canadian border? Not very. Fox News set out from this state forest preserve less than two miles from the Canadian border on a mid-afternoon hike, where we saw some wildlife and a few other things.

After hiking about 40 minutes, we were pretty sure we were about half a mile into Canada. Maybe a bit more.

We walked along an old logging road that hasn’t been much used of late. No one stopped us on our way into Canada, and we didn’t anticipate anyone stopping us on the way back.

We did not get caught.

What’s more, these paths and old logging roads are not new to intelligence officers on either side of the border. Paths like this were used by Soviet operatives during the Cold War.

Now, it’s a war on terror that is America’s top defense priority. But with the border mostly unguarded, Canada’s open-door immigration policy is the battlefront.

Steve Brown is an author, radio broadcaster and seminary professor at Reformed Theological Seminary in Orlando, Florida.