His ability is only usable once each referendum, even if he unlocks somehow during the referendum.
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Michael Luther
G3Camarilla: You may lock Michael during a referendum to change the votes and ballots of a Camarilla vampire to votes and ballots of your choice. When Michael enters combat, you may draw 1 card. Discard down to your hand size afterward.
Rulings
Cannot be used during a referendum that is automatically passing.
The ability can be used when in torpor.