There is precedent.
This is a cause whose justice nobody can doubt, and which has every moral demand on our consciences and our resources. The Western world- and especially the Christians in it (not, as they have sometimes dreamed and as their critics sometime maintain, a majority, if commitment to the Faith is a criterion, but still a formidable number) have the chance to make a difference for people being overtaken by a great darkness.
Believers and unbelievers alike should rally to this cause. If we can't find common ground on this, it's hard to imagine that enough of a moral consensus remains among us on which to even maintain a common society.