The reporting that supported the Invasion of Iraq is not surprising. Jingoism has been the hallmark of the press from the days of the Revolution. "Cry Havoc, and loose the dogs of war" has been the press motto from the beginning.
The Mexican American war was trumpeted by the press as part of America’‘s "Manifest Destiny" and started under the pretext of a border dispute along the Texas Mexican border.
Before the Spanish American war, William Randolph Hearst sent a reporter to Havana. When the reporter sent a message telling Hearst there was no evidence of war. The newspaper magnet sent a return message, "You provide the reporting and I’ll provide the war" Hearst was in a circulation war with Joseph Pulitzer and between the two, America finally did start the conflict.
British propaganda charging the German Army with nonexistent atrocities was printed without challenge in the American press. The Brits had cut the transoceanic cable from Germany to the U. S. so there was nothing to counter the most loathsome charges of Germans raping Belgium women and skewering their babies on bayonets. None of this was true, but it created a demand for war against the loathsome Huns. Wilson resisted this effort until the torpedoing of the Lusitania, then America entered "The war to end all wars"
Isolationism couldn’t keep the American press from championing the beleaguered British and its hero Winston Churchill, or FDR from secretly and illegally helping England during it’s most desperate hours. World War Two was the one truly just war fought by the United States, but it took the Japanese attack on Pearl Harbor before the public would support it. Had Hitler not declared war on America, FDR may have had difficulty convincing the public to fight Germany.
By the time North Korea invaded the South, America was in the throws of Cold War Hysteria, so there was no need for a propaganda blitz to get support for American participation. We entered the conflict armed with a United Nations resolution, and the support of the West.
Our entry into Vietnam was gradual until the action in the Gulf of Tonkin gave LBJ the excuse to escalate our involvement. The reality is the first attack did happen. One of the Torpedo Boats that participated in it is displayed in a museum south of Hanoi. The second was caused by an error in the interpretations of radar readings. The press supported the war until disillusioned by the Tet offensive. Then with a growing anti war movement at home the media turned against the war forcing Johnson to forgo running for a second term.(The story of Tet is fascinating and not known by Americans even today) Nixon had a plan, so secret, that he didn’t know what it was. We finally got out, losing our first war.
The Bush administration exaggerated many of the reasons for invading Iraq, but they had reason to believe Saddam did have chemical and biological weapons. The press went along until WMD was not found and then turned against the war.
All these wars are examples of the adage "Truth is the first causality of war"