Not everyone cares about the conflict footprint that comes with oil from Iran's loathsome regime. Plenty of countries are content to patronize a government that not only brutally tramples basic human rights, degrades women, and persecutes gays, but also uses the currency it collects from oil sales to build nuclear weapons so it can threaten and potentially attack its neighbors.

When France's president, Nicolas Sarkozy, recently floated the idea of slapping an embargo on Iranian oil to pressure the mullahs to stop their dangerous and illegal nuclear arms race, he won support from Britain, but the rest of the European Union wasn't hot on the idea. They're just fine punishing ethical Canadian oil, but debated over punishing Iran's conflict oil.

But supporting conflict oil doesn't just mean promoting terror, persecution, murder, and war -- though it certainly does mean all those things. It also means promoting instability and risk. That's what the Europeans, and other importers of Iranian oil, are discovering right now. That's because the Iranian autocrats have declared that if the world continues to bring pressure to bear on them over their illegal nuclear program, they'll choke off world oil supplies by closing off the Strait of Hormuz.

In short, that could be disastrous to a world economy that's already perilously fragile. The Strait of Hormuz is the main channel through which Middle Eastern tankers transport oil for export from Saudi Arabia, the United Arab Emirates, Kuwait, and Iraq. In addition, about 15.5 million barrels -- or a third of all ocean-transported oil and liquefied gas worldwide -- moves through the six kilometre-wide strait. Even for those countries, like the U.S. and Canada, who aren't clients of the Shariah oil state, the spike in oil prices that would be caused by such a major disruption of supply could be devastating.

This is what a world at the mercy of conflict oil looks like. It's a hostage situation. We either directly support the horrendous rule of the worst dictators on earth and, if we don't, they can cause the entire world great economic pain and, potentially, even spark warfare. As the National Post reports, Iran's decision could very well "trigger military conflict with economies dependent on Gulf oil."

Canadian oil isn't just ethical because it comes from a nation that stands for the highest standards of human rights, gender equality, minority protection, environmental conservation, democracy, accountability, and peace. It's ethical because we don't use oil as a weapon. Canada wants nothing more than a secure, stable oil supply -- the same thing oil-importing countries desperately want, too.

Countries that shrug off the vast ethical difference between Canadian oil and conflict oil from countries like Iran can typically afford to do so because it doesn't usually affect them directly.

Most of the time the difference is psychological: It's about values and the fate of persecuted people in foreign lands. Once in awhile the cost of choosing conflict oil becomes very palpable and very direct; 9/11 was one of those times, when Saudi oil money was linked to Al Qaeda.

If the world economy ends up ruined by a belligerent Iranian regime bent on nuclear domination, we'll all be paying dearly for the decision of some countries to support Iran's conflict oil, too.

Follow Kathryn Marshall on Twitter: www.twitter.com/KVMarshall