Not sure I understand what the Titanic has to do with the Constitution. The question that remains is this. Did Hussein at any time after the Gulf War represent a clear and present danger to the borders of this nation of states anymore so than any other third world dictator? If the WMDs are there, you may have an argument (albeit a very limited one). If he did not then he represented no more of a threat than any other nation that supplies and arms terrorists, say like Saudi Arabia, who our government calls an 'ally'.
The Constitution was not written with the intent of pre-emptive action against any nation that may in the future present a threat. Thought processes such as that came from those that hold Wilson's interference in WWI and FDR in high regard, namely the neocons