"America supported Saddam in the first place!": True, but a fallacy that doesn't help any anti-war arguments.
It's not a direct anti-war argument, but there is an important point here. It's not just that the US supported Saddam before, but that in many cases it's exactly the same people. The people who are now saying that Saddam must be removed because he has WMDs are the same people who gave him those WMDs and encouraged him to use them in the first place.
If somebody says that Saddam must be removed because he had WMDs, the next logical question is why wasn't that an issue before? We gave him those WMDs, why is it now a problem? How can the same people that encouraged him to use those WMDs now being saying that he has to be removed because he used them?
It's the inability by the pro-war camp to answer those questions effectivly that makes it an anti-war issue.
Jay