The problem with the "fight them there or fight them here" arguement is that Afghanistan served the purpose.
The problem with the "base in the middle east" arguement is that we had established bases in Saudi we GAVE UP to invade Iraq.
The problem with the "democracy in Iraq" arguement is you can't force democracy on a people who don't want it, and people who aren't will to fight for their own freedom will never keep it without a constant and permanent US presence to force them to be free
It damn well better be about the oil, that's the only way the arguement that Iraq is part of the WOT makes any sense at all.
Terrorists in charge of the oil supply is a grave and imminent threat.
Of course invading sovereign nations to gain control over their natural resources, whether we pay for them with our debt-money or not, raises moral questions we don't want to have to answer truthfully, so we have all these other arguements why we're there.
Right or wrong thing to do I don't know, it depends on whether you think it's worth it to compromise principle to maintain our way of life, and whether or not the peak oil theory is correct, which is so obfuscated nobody outside the boardrooms of the big oil companies and the national security briefings of the major powers knows for sure.