Nearly eight years ago, the Millennium Bomber, Ahmed Ressam, traveled from Montreal to Vancouver, B.C., then tried to enter the United States by ferry at Port Angeles, Wash. In Ressam’s rental car was 130 pounds of explosives that he planned to use for a pair of detonations at Los Angeles International Airport. The first blast was planned for a crowded spot. The second was designed to obliterate those attempting to rescue the victims.

It was Ressam’s circuitous route to Seattle that raised suspicion in a Canadian border agent. His fidgety mannerisms in front of a U.S. customs agent proved to be his undoing. Since then, billions of dollars have been spent on border security, but most of it has been concentrated on the southern border with Mexico as politicians attempt to placate angry U.S. citizens who not only want tighter security but the flow of illegal immigrants to stop. Another $30 billion to $36 billion is earmarked just for a fence.

Meanwhile, the border that Ressam chose remains relatively easy pickings. Oh, it now takes longer to cross at popular checkpoints, such as Blaine, Wash., near Vancouver, B.C., but government agents recently discovered that crossing at less populated areas was a breeze. Fortunately, Ressam didn’t choose a rural crossing point, but how much longer can that luck hold as most security dollars flow to the south?

The Government Accountability Office tested the Canadian border at four undisclosed locations and found that terrorists armed with radioactive materials could easily cross. That’s because the northern border is twice as long but has one-tenth the number of U.S. agents.

GAO workers were able to carry a large red duffel bag across the border at all four sites without being intercepted. The faux terrorists reached their sites via side roads. They said that state roads near the border didn’t appear to be monitored. They were videotaped, but in some cases there were no agents on hand to react to their presence. Once, an alert citizen notified border agents, and the GAO agents were delayed for a brief inspection. But their car was not checked. Neither was the duffel bag.

If a nervous Ressam had crossed at these sites, he might have been able to carry out his terrorist plot. Another terrorist probably could.

In response to the GAO report, U.S. Sen. Patty Murray said, “We simply cannot accept this level of vulnerability.”

For the better part of eight years, Murray has been pushing for more border agents and more high-tech surveillance and communication equipment. The Sept. 11 attacks resulted in some improvements, but as the GAO experiment shows, it isn’t enough.

Let’s hope it doesn’t take a successful terrorist strike to prompt action this time.