Better we simply remove all the originals, put them on display behind bullet-resistant glass, and then replace them with facsimiles.  At least then the original appearance of Iolani Palace can be preserved.  The big difference between a standalone painting or sculpture and the glass panes at Iolani Palace is that the latter form part of an architectural and aesthetic whole.  Sure, shielding the originals in situ with some sort of tough plastic or glass frame would work as far as protecting them from vandals, but then you'd now have introduced at the very least a visible reminder that Hawaii's own people can't be trusted with preserving them - for all the tourists to make note of and photograph.

In any case, the point of my earlier comment was to emphasize how much more intolerable this kind of wanton destruction is.  A glass store window on King Street can be shattered by a vandal too, but its loss isn't nearly comparable to the loss suffered again at Iolani Palace.