How did differences between conservative and liberal goals lead to conflict in Europe?

When? There have been lots of conflicts in Europe...How did differences between conservative and liberal goals lead to conflict in Europe?
Indeed, when? Are you referring to pre-Nazi Europe, contemporary Europe, or some other period such as that of the Enlightenment and French Revolution? One might suggest, for example, in today's context, that liberal goals of sexual liberation, involving massive contraception and abortion, have led to a birth dearth. The resulting vacuum has led to a resurgence of Islam in Europe and conflicts between immigrant Muslims and ethnic Europeans.