An affirmative vote on which of the following subsidiary motions may not be reconsidered?

The motion "lay on the table" is designed to temporarily set aside a pending motion that is currently under discussion. Once this motion has been adopted, it cannot be reconsidered. This is because "lay on the table" is used to interrupt the flow of business and allows the assembly to focus on more pressing matters. Once the assembly decides to table a motion, it effectively removes the motion from consideration and does not allow for a further discussion or a reversal of that decision through reconsideration.

In contrast, the other motions such as "postpone indefinitely," "previous question," and "main motion" can be reconsidered. For example, a "postpone indefinitely" motion essentially allows for later discussion of the original matter should circumstances change. The "previous question" motion is a tool for closing debate and calling for an immediate vote; it can also be reconsidered. Lastly, a "main motion," which is a proposal to take a specific action, may also be reconsidered to allow for further debate or to change the outcome of the vote. Therefore, the distinct nature of the motion to "lay on the table" separates it from the other options in that it cannot be brought back for reconsideration once passed.