Catholic, non-Catholic and all joking aside: would you really consider serving on the front line on God's orders?
And this isn't a wind-up, either. It stems from a conversation recorded in an undercover programme broadcasted in the UK that infiltrated a chapter of a far-right group in the UK known as the North West Infidels, who march in opposition to what they perceive to be the Islamification of Europe. They're rumoured to have attracted intense interest from MI5 in the wake of the Anders Breivik massacre.
The Pope is not God and, as I am Protestant, for me he doesn't speak as God.
And I can't imagine God sanctioning a Crusade. So yes, if He did, I would obey orders. But as I can't fathom such a thing happening, I think it is pretty well moot. I have heard God speak from a person's lips to my ear many times. But there is not a soul on Earth who I believe to be commissioned to speak for God.
So. . . .I pretty much look to the Constitution and those wonderful men of fiath who gave it to us as our guarantee that the Church would never again have the power to call us to arms to do anything. I think that was their intent for the government too, but the USA deviated from that for some time. We now again have an all voluntary military.