The other day Cerberus asked the question- "what if the US had not invaded Iraq?". The question related to the situation in Iraq itself, but I think it important to look at how the Iraq invasion has impacted the international scene.
There is no question that the Iraq war has damaged American prestige within the world community on several fronts. America now has little credibility on issues of intelligence, which has a direct impact on the other world "hot spots". The world community is suspicious of any American claims and this hurts their diplomatic effectiveness. Coupled with the torture scandals, and you have an America which lacks the moral clarity to champion human rights.
The diplomatic chasm that still remains as a result of Iraq has led to a hardening of opinion and essentially divided the first world governments. There also exists a lack of will to deal with other "problem" areas, as there is no appetite for any talk of military action, with visions of Iraq fresh on everyone's minds. I would argue that the current Iranian crisis has reached such a critical stage as a result of the failed Iraq war. Iran has been able to advance its nuclear program with little concrete concern of ramifications, as the world shows little desire for a real conflict. Had the Iraq war ceased to exist, it is reasonable to see a world community far more united, with the necessary military threat to force concessions. Internally, the American public and elected officials would be far more "hawkish" with regards to Iran, if not for the trepidation over Iraq. Can anyone envision a scenario now where the U.S. congress gives Bush the green light for military options on Iran? Any administration arguments for a tactical strike on Iran will be met with a "cried wolf" mentality. A real threat may be questioned because a manufactured threat was manipulated. This situation may well effect American foreign policy for a generation.
For Canada, I have little doubt that our role in Afghanistan would be much different if not for Iraq. The American military was obsessed with Iraq, at the expense of the fragile situation in Afghanistan. Had the focus remained on Afghanistan, I seriously doubt there would be any present day discussion of Taliban remnants or Al Qaeda lurking on the Pakistan border. The security situation would be far more advanced, with Canadian troops acting in their traditional role of peacekeepers, as opposed to makers. Canada's decision to send troops to Afghanistan relates to the American's need to replace their thinly stretched forces. Our role allows the American military more latitude to continue the presence in Iraq. It is legitimate to ask whether Canada would even be in Afghanistan if not for Iraq.
When the Americans invaded Iraq, it provided extremism with potent fuel, as nightly images of dead Muslims were broadcast throughout the world. Muslim extremists were given concrete proof that America was an imperialist nation, that wanted to control the world. How can the west counter the reality on the ground? The Iraq war has set the stage for a future war of cultures, as an entire generation is now indoctrinated with suspicion and hatred. I'm not sure we can comprehend the future consequences of this misguided war. The Iraq war will haunt the world for decades to come and may well prove to be the watershed moment for a wider conflict.