re: If the US had not invaded Iraq....
...it wouldn't be losing the war in that country.
I'm pretty sure democrats would not have put themselves in a losing situation. After all, winning a battle obviously wasn't enough to win the Iraqi's hearts.
About Afghanistan, because it has been approved by the UN, it is a shared responsability and countries willing to remain members of the UN (vital for international relationships) arel sharing the burden with the US.