Unions can't force their members (or non-members) to strike, except for the fact that if as a member you refuse to join a strike organised by your union you might be expelled. Attempting an individual strike without the backing of a union would leave you no protection from retaliation and would likely get you fired. The unions themselves are relatively limited in how and when they can organise legal strikes.

Employers on their part have access to a similar tool in the form of lockout, where they bar employees from coming into work and stop paying their wages. An employer targeted by (legal) solidarity action can't fire their striking employees, but could respond with a lockout.

There's a provision that disallows strike action where it would harm public order, which would apply to the police union refusing to protect Tesla property.