I particularly like the point that the invasion of Iraq went astray in part because of its exclusively secular approach. A lot of people misinterpreted a perfectly normal (for any Christian) remark by Bush about seeking divine guidance as some sort of claim of divine inspiration for the invasion.
It's probably true that conservative Christianity leads to a rather dualistic mindset and thus tends to favor the demonization of enemies (this is one of the places where "conservative" and "orthodox" definitely don't mean the same thing). But the explicit reasons I hear from conservative Christians for their support of the war sound almost entirely secular to me. I don't think their problem is that their thinking is dominated by religion--the problem is exactly the opposite. They use Romans 13 to justify full support for whatever bloody actions the government may think necessary, and anyone who questions those actions is allegedly engaging in some sort of liberal utopianism that ignores human sinfulness.
In other words, the war in Iraq is not and has never been a holy war driven by Christianity. Like most modern wars, it's driven by perceived national self-interest, but it derives fuel from bad political theology that hands the job of moral reasoning over to the state, while lending the state's actions [purported] divine approval.