What does 'union security' refer to in the labor context?

In the labor context, 'union security' primarily refers to provisions that require employees within a bargaining unit to either join the union or pay dues to the union. This concept is designed to ensure that all workers benefiting from union representation are contributing to its support, thereby promoting solidarity and financial stability for the union.

This requirement serves several purposes. It helps guarantee that the union has the resources necessary to effectively represent its members in negotiations and grievances, and it prevents situations where some employees might benefit from union representation while refusing to support the union financially. Consequently, it enhances the bargaining power of the union as a whole.

The other choices describe concepts that are contrary to the standard understanding of 'union security'. For instance, encouraging employees to join the union speaks to voluntary membership, but does not capture the mandatory aspect that defines the security arrangement. Policies that allow employees to opt out and measures that prevent union membership explicitly undermine the integrity of the union’s financial and organizational structure. Thus, the correct choice reflects the foundational principle of mandatory union membership or fee payment intended to secure the union's resources and influence.