One of the arguments one frequently hears with respect to Iraq is that the world must not make the same mistake that it made back in 1939: it must not appease an evil dictator bent on conquering the world. Apart from the fact that there's precious little evidence supporting the assertion that Saddam Hussein wishes to conquer the world, and that his purported weapons of mass destruction are certainly not up to the task even if they really exist, the historical comparison fails to agree with historical facts. The world is definitely not doing what it did in the 1930s: it is not appeasing an evil dictator, and it is not ignoring his deeds. Consider the following points:

When Hitler reoccupied the Rheinland, the world stood by and did nothing. Saddam Hussein is prevented from occupying Kurdish-controlled Northern Iraq by the imposition of no-fly-zones that involve proactive measures such as combat air patrols that routinely attack air defense installations and other military targets.
When Hitler annexed Austria on the basis of an historical pretext, the world stood by and did nothing. When Saddam Hussein annexed Kuwait on the basis of an historical pretext, a worldwide coalition, with the backing of the United Nations, used military force to liberate the occupied country.
When Hitler rearmed his country in defiance with the League of Nations and the Versailles peace treates, the world stood by and did nothing. When Saddam Hussein lost his war against the Coalition, the world demanded that he get rid of his weapons of mass destruction, set up a regime of inspections and sanctions, a regime of export/import controls.

I have this nagging feeling that leaders who compare the present to the past while disregarding facts of history wish to see themselves as the Winston Churchills of our era. They tend to forget that Winston Churchill is revered because he advocated that we do what we didn't do then (and did do in the 1990s.) He's not revered because he'd have started WWII even if Hitler had failed to do so!