Different areas have some interesting laws about not being able to fire unionized workers who are carrying out a codified labor dispute with no contract and other laws about not crossing the picket line.
You generally may not be able to fire unionized workers on strike (depending on what it’s regarding) but at least in the US it’s not against the law to hire temp workers during a strike. The only power a strike has is shutting down operations, if the strike doesn’t do that because of scabs, it’s essentially ineffective. In my opinion any labor union that calls a strike that doesn’t result in work stoppage is not helping its workers.
