Church may not be bluffing, but it shall be the will and enthusiasm of the faithful Theocracies to uphold it. Who knows how long it will take for the crusaders to actually mobilize.
lol.
You think they're just now starting to mobilize?
Basically, this crusade started when two things happened:
1. Mathurin said defending Terran would be a good cause for a theocracy
2. Phantaria declared war
It just took a little while to get the official nod. But realistically, planning and early mobilization began then.