Which of the following motions is generally decided by a two-thirds vote?

A motion to limit debate is typically decided by a two-thirds vote because it affects the rights of the members to discuss an issue. Limiting debate can restrict members' opportunities to express their views fully on a particular topic, so a higher threshold is required to ensure that there is a strong consensus among the members before such restrictions are implemented. This requirement helps protect the democratic process within meetings by ensuring that significant changes to how discussions will occur have broad support.

In contrast, calling for a recess, raising a question of privilege, and introducing a new main motion usually only require a simple majority because they do not fundamentally alter the rights of the members in the same way that limiting debate does. These actions can be considered routine and therefore do not warrant the additional consensus needed for more impactful motions like limiting debate.