What would the Altmer do if Crystal like law reappeared? Suppose it gets teleported with the people who were inside it from just before the daedra attack to the time of the Skyrim game. Not saying this is at all plausible, I was just wondering. I was thinking about this because my understanding is that the Thalmor are trying to destroy the towers to unmake the mortal world. So would they be willing to re-destroy a tower which had been so iconic in their culture? And if the Thalmor were willing, would the rest of the Altmer let them?

After some soul searching I think they would return to their xenophobic/isolationist ways, while also maintaining large military holdings around their island.

My understandment has been that Altmer/Thalmor started campaign for Cyrodill because they needed new tower to renew their source to gain Aether magic because they lost Crystal as Law. So i don't think they would destroy it, they need Tower and power it provides to un-make Mundus... But... Why not to have two towers? So i guess Thalmor might still continue their campaign to gain White Gold as well.

Granted i haven't much studied subject. Only impressions,which are largely speculative, i've formed based on Skyrim.