Final answer:
Before a strike can take place, the union membership must vote for the strike, ensuring it has the majority support of the members.
Step-by-step explanation:
According to the information provided about organized labor and union formation in the United States, before a strike can take place, the membership of the union typically must vote for the strike. This democratic process ensures that the collective action has the support of the majority of the union members. While the president can declare a "cooling-off period" during disruptive strikes and in certain cases, all workers may be required to join a union as a condition of employment, these details are separate from the initial voting requirement for the authorization of a strike.