America's northern border is twice the length of its southern border, but it has only one-tenth the number of agents. If each of them were standing guard at the same time, they'd be spaced four miles apart.
The border is the responsibility of the International Boundary Commission. The US-Canadian commission uses 5,528 markers to define the line and keeps clear a strip of land called the "vista." In North Dakota, that means dotting the expansive plains with small obelisks. In Washington State, it means clearing a swath of forest 20 feet wide.
Despite the border's length, fewer than a third of the people crossing into the US by land come from Canada. In 2004, that turned out to be 191,000 a day, on average, compared with 660,000 entering from Mexico. About the same number on each border came by bus. Mexico won hands down in pedestrian traffic, even when restricted to legal crossings (132,000 vs. 2,300 a day).
Blaine, in the northwest tip of Washington, is one of the busiest northern border crossings, at least in the western US. Hannah, N.D., is one of the least active, last year averaging just under 3.2 cars a day from 5 p.m. to 10 p.m. That's why border agents next month will start closing it at 5 p.m. daily.
Such lean security is not unusual for a sparsely populated frontier, especially one known as the world's longest undefended border. But the war on terror and rising concerns about illegal immigration are challenging that tradition. Next year, Canada will begin arming its border guards, who until now have carried only pepper spray and batons. In 2008, US border guards, already armed, will begin demanding passports of all drivers crossing into the US.
The only terrorist known to be caught entering the US by car was unmasked in 1999 because a border agent in Port Angeles, Wash., noted his nervous behavior. Agents found explosives in his car, destined for Los Angeles International Airport. He is now serving a 22-year prison term.
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