A fundamental aspect of the Iraq war is that American losses happened in drips over a decade. 5,000 dead soldiers over 10 years is the proverbial boiling frog. We didn't notice how bad it was until the body count was already enormous.Yes, despite the parallels, it is quite a different situation politically. Add to that, Iran 2019 is not Iraq 2003. A conflict with Iran would not be like the Iraq War. It would be worse.
Iran will be killing hundreds of American soldiers in the opening hours of a shooting war. They have no chance of winning, but they are not going to be rolled like the Iraqis. US boats will sink. US aircraft will be shot down. Enemy soldiers will be highly disciplined and well equipped. It's going to be a slog with an enormous body count, and the idea of POTUS Donald Trump addressing the media after a hundred sailors drown in the wreckage of an amphibious assault ship is just ridiculous.