Actually, it's both
Michael O'Hanlon of the Christian Science Monitor swims against the prevailing current of U.S. media opinion and lays blame for Canada's missle-defence refusal at the feet of President Bush:
Many are viewing this as a slap in the face from Ottawa to Washington, and a change in the position Canada seemed to be taking a year ago. They expect it to poison relations between the two neighbors - ensuring, among other things, that next month's three-way summit with Mexican President Vicente Fox will fail to make progress in broadening NAFTA. It would seem that the knee-jerk liberal Canadians just could not get over their nostalgia for the ABM Treaty, as well as their visceral dislike of missile-defense systems.
This interpretation is badly mistaken. The Bush administration made major diplomatic errors in handling this topic with Canada. It asked for blanket endorsement of an open-ended US missile defense program, rather than for specific help with specific technical challenges and defensive weapons. This was a fundamental mistake, and the US has mostly itself to blame for the resulting fallout.
He's at least partly correct. Even Stephen Harper has said that Canada shouldn't commit to the plan until we know exactly what is being asked of us - now and in the future.
What O'Hanlon fails to realize is that while Bush made undeniable diplomatic mistakes dealing bluntly with the stand-for-nothing, finger-to-the-wind Liberals, many Canadians - especially in the soft Liberal underbelly of Quebec - have profound nostalgia for the ABM treaty, and really do harbour a visceral dislike of missile-defence systems. The two scenarios aren't mutually exclusive.
In fact, one could argue that it's principally because of Canadians' knee-jerk opposition to all things military, American, and Republican that Bush should have soft-pedalled the issue, instead of proceeding in his typical forthright style to challenge PM Dithers publicly.
O'Hanlon goes on to reach just a little beyond his grasp with the following passage:
What Bush administration officials need to remember is that they almost surely could not get blanket endorsement for all of the above missile defense systems even in the US. Congress has provided funding just for deployment of a limited land-based system and for research and development of other possible concepts. It has not bought into a grandiose architecture of the type that many Pentagon planners still envision. Nor is Bush unwise enough to request such an open-ended endorsement from Congress.
Indeed, his budget request for 2006 cuts missile defense, in recognition of the facts that the relevant technologies are proving slow to develop and that other, nonmissile threats seem more pressing. Yet it was at this moment the president asked Canada for something he probably could not get from the Republican-controlled legislature in his own country.
But that's not really a fair comparison, is it? In Canada, Bush seems to be asking for moral support. In the U.S. Congress, he's most definitely asking for money. I can tell you, if he was asking for money in Canada, I'd be lining up with those opposing the plan at this point. Morally, I think defensive military hardware is easy to justify - unless the bad guys attack, it doesn't threaten anyone. But spending gazillions of taxpayer dollars on a system whose efficacy could be charitably described as speculative, to combat a threat that realistically ranks lower than that of a lone jihadi dumping a shoe-box of anthrax-powder into the air-conditioning system at Mall of America requires a leap of faith Canadian politicians would be foolish to make.
The bottom line is that Canada is a high-maintenance diplomatic companion in North America, the Bush administration has no patience for high-maintenance relationships, and as a result, Ottawa's influence in Washington continues to be negligible. Until the Bush administration learns to be less of a bull in the Canadian china-shop, or until the Martinis become vertebrate, that situation is unlikely to change.