I'm reminded of Chinese dynasties. Eseentially very dynasty that wasn't toppled by someone else first (e.g. Mongols) finally crumbled when it failed to deal with a famine. Mass unrest combines with the collapse of 'divine right', and everything switches to war and chaos.

If magic thinking is unavoidable, then the best hope going is to relegate it to a category that can collapse and be rebuilt without destroying stability. The last thing you want is to tie your government to a condition that's guaranteed to fail eventually.