Crossing an ocean to bomb a nation "just in case" they harbor a few terrorists is about as unChristian an act as I can imagine. God will not be mocked by claiming this is His war. It is not.
Here is a link to the Iraq War Resolution.
Note that there are 23 separate "Whereases". I.e., 23 separate reasons for taking action. Recall that it was passed by a Democrat-controlled Senate and the majority of the Democrats voted for it, as well as every Republican.
Recall also that, as to the most serious "Whereas", the presence of WMD was an unquestioned fact on the part of every major intelligence agency and the UN inspectors -- who, upon leaving the country in 1998, had an inventory of the remaining biological warfare agents (which ran into the hundreds of tons).
Further note that some WMD were in fact discovered (though most may have been shipped to Syria). And vast stores of WMD raw materials (550 T of yellowcake,e.g.) and equipment (centrifuges, etc) were also found. While there might be a question about "stockpiles", there can be NO question about either "intent" or "ability".
Moreover, we didn't "cross the ocean". We were already there, remember, being responsible for policing the no-fly zones and exercising our responsibilities in the wake of Gulf War I.
That action had been ended by a truce -- not a treaty of peace. It was Hussein's responsibility to live by the terms of that truce. He did not.
Any President who did not take action to quell this threat after the post-9/11 reality would've been guilty of dereliction of duty.
I don't pretend to know how God might feel about it. But I do know that America's motivation was honorable. And that we removed a truly evil regime and liberated 25 million people.
That would, I suspect, count for something...
I suppose that the "War between the States" was a bad idea as well according to that sort of reasoning.
It is OK with me if you think so, but that is where that sort of reasoning ultimately must bring you.
It is pacifism.