The federal government plans to give an unspecified number of American police agents carte blanche to carry guns in Canada. It insists that in the post-9/11 world it is just being sensible. It is not.

Few things are more crucial to a nation's sovereignty than its control over legalized violence. It is quite often lawful for the police to shoot you. It is almost never lawful for you to shoot the police. We accept that arrangement only because those who have been given this remarkable life and death authority are in some sense "ours" – they are responsible to governments that we elect.

Ottawa's plan would dramatically change this relationship. It would introduce a whole new array of armed peace officers into this country that are answerable to a foreign power.

Stephen Harper's government, which quietly published these proposed regulatory changes in its Canada Gazette last weekend, suggests the move is designed primarily to accommodate armed air marshals who routinely fly back and forth across the border. But it also says the arrangement would apply to other situations, including "various cross-border enforcement initiatives between Canada and the United States."

This is bureaucratese for open-ended. It means the new law could apply to just about any U.S. agency – from the FBI to Homeland Security to Buffalo police.

Presumably, foreign agents would be allowed not just to carry weapons but to use them. Otherwise what would be the point?

And if, under this new regime, a U.S. agent killed someone on Canadian soil, to whom would he be responsible? Who would investigate? If the shooting were deemed improper, who would lay charges or impose discipline?

Until the `90s, no foreign peace officer was allowed to enter Canada armed – a rule that particularly irked U.S. secret service agents assigned to protect their president during official visits. That rule was relaxed in 1995 specifically to let foreign leaders bring in armed bodyguards. However, these bodyguards – and anyone else who wants to bring a gun in or out of Canada – must apply for one-time permits.

For armed air marshals who make regular cross-border runs, this can be a bureaucratic process. But it seems to work. And it surely can't be more onerous than any of the other security provisions imposed on air travellers.

So why loosen the rules? The government offers no coherent reason – except to say that in some instances peace officers cross the border several times a day. This may be true. But unless these unspecified agents are planning to police someone else's country, they could simply leave their guns at home.

And that is the rub. Since 9/11, the U.S. has already expanded its security and police presence in Canada. The FBI has opened new offices here. The public inquiry into the imprisonment and torture of Maher Arar revealed that agents from the FBI and other unnamed U.S. agencies routinely took part in RCMP meetings dealing with his case. Undercover U.S. agents monitored the Six Nations standoff at Caledonia. Their presence was exposed publicly only after native protestors hijacked their car.

But so far, none of these foreign agents has been given broad legal authority to arrest, detain or shoot anyone in Canada – which is why they are not allowed to carry weapons here. That privilege is reserved for Canadian peace officers answerable to Canadians. Now, Ottawa plans to erode this important distinction.

For a country that claims to be sovereign, this is a bad idea.

Thomas Walkom's column appears Thursday and Sunday.