Despite almost four years of effort and billions of dollars spent, the greatest threat to U.S. security remains a porous and troubling border.

Long lines and intense security screenings for everyday people have done little to improve the situation. Illegal immigration along the southern border with Mexico hasn’t slowed, even with self-appointed, civilian border guards roaming the Arizona desert.

Now comes word that Canadian border security, which has increased greatly the amount of time necessary to travel between the two countries, is mostly for show. It’s no surprise that the extensive border, dotted with unmanned crossings, presents ample opportunity for people to come into the country undetected. But even the manned security stations have a problem with common sense.

Nurses, who travel daily between Canada and Calais, see their medical bags searched and face questions routinely. But a man accused of killing two people, carrying a bloody chain saw, knife, sword and brass knuckles, is able to pass through security unmolested.

Granted, border guards didn’t know about the deaths of two people in Canada when they allowed Gregory Despres to enter the country at Calais. But they could have – and should have – known that he was due in Canadian court on the day of his trip. And they should have recognized that someone claiming to be an assassin and in possession of several potentially deadly weapons shouldn’t be allowed in the country, at least without a more thorough investigation by Canadian authorities.

It’s easy to argue that Despres has not been convicted of a crime and that strange behavior shouldn’t exclude otherwise law-abiding people from visiting the United States. But given that an airplane traveling from Europe was diverted because the former Cat Stevens, a convert to Islam, was on board, it’s reasonable to expect a more cautious approach at land crossings.

Arrested in Massachusetts two days after crossing, Despres now is awaiting extradition to Canada.

What once was a simple process to go back and forth between the United States and Canada has been made considerably more complicated. There’s little indication, however, that the delays and imposition on commerce are yielding real security gains. It’s time to re-evaluate the approach to protecting the country’s northern border. The system now is ineffective.