Different sets of rules for our troops vs the insurgents in Iraq

I am really tired about the hyping of white phosphorus as an 'illegal or immoral' weapon.
The US troops in Iraq use it for smoke screens, to make it difficult for the insurgents to kill them when moving around. Or it is used to illuminate areas.

The US troops are not targeting civilians with this. Let us remember what the insurgents were doing in the city in the first place!!!