If you doubt me on this, let's look at Canada in Afghanistan. Canadians, because they do not fight in Iraq, are not constrained to call Afghanistan the "good" war. Canadians dissent a great deal on their government's decision to fight in Afghanistan. And as Strategypage writes, the Taliban have noticed:
The Taliban are increasing their attacks on Canadian troops, apparently because the Taliban are keeping track of Canadian politics via the Internet. The Canadian government is under pressure the opposition to get out of Afghanistan, or get other NATO countries to take a greater role in combat operations. NATO is split over how to deal with the Taliban. About half the NATO troops in Afghanistan are from countries that will not allow their soldiers to go south and fight the Taliban.
So far Canada is paying the price of dissent without breaking.