Element,
I don't know the right or wrongs of Mistral's summoning, except that
it was performed in Shallam, which in itself is against the Citie's
laws.
However as to its power, It was something the Church was willing to
give up in return for the peace offered by the treaty, and whilst a
few with the skill did use it they were punished in accordance with
the treaty.
Ashtan chose, and ironically Mistral was a key element in the
choosing, to end the treaty, and thus church members are free to use
convocation in anyway that they wish.

Isildur.

Penned by my hand on the 10th of Valnuary, in the year 240 AF.