To help sway population opinion. Look at 2nd Iraq war, polling after the invasion still had swathes of the population believing Saddam was linked to 9/11. Government plus the media did that to help back the war.

Remember the incubator story from the first Gulf war. A key inflection point to move the American public and Congress toward supporting war in Iraq was the gruesome 1990 testimony of a Kuwaiti girl named Nayirah, who described how Iraqi troops killed 312 babies.