One of the tactical mistakes that far-left types frequently make is that they write off people with strong religious convictions as being unreachable or unreasonable. What they fail to realize is that one of the reasons that Christianity is so popular is that many of its moral precepts make perfect sense whether you happen to believe in magic or not.
When Jefferson wrote "we hold these truths to be self-evident" he of course meant that certain things are so obvious that they don't need to be defended. One of these self-evident truths is that if you're of the opinion that human life is sacred then you should oppose war with at least the same degree of fervor that you spend opposing abortion.
If on the other hand, your theology is based on the premise that pleasure is sinful but that pain is desirable, then it makes perfect sense to cheerlead warfare. Such thinking should be exposed at every opportunity.