What phrase describes the situation when workers are required to join a union as a condition of employment?

The phrase that describes the situation when workers are required to join a union as a condition of employment is known as a "union shop." This term indicates that while workers may be hired without being union members, they must join the union within a certain period after being employed. The purpose of the union shop is to ensure that as new employees come into a workplace, they are integrated into the union's membership, thereby strengthening collective bargaining power and solidarity among workers. This setup is often used to help maintain a robust labor force that can negotiate better working conditions and wages collectively.

In contrast, the other phrases refer to different concepts within labor relations. A "closed shop" requires workers to be union members before they are hired, effectively excluding non-union workers entirely. The "open shop" allows workers to choose whether or not to join a union without any requirement to do so. "Right to refuse" does not pertain to union membership or conditions of employment within union contexts but rather refers to an individual's ability to decline certain actions or demands. Understanding these distinctions is key to grasping the dynamics of labor unions and employees' rights within the workplace.