Final answer:
The chair's ruling on a motion to 'lay on the table' when there is no urgent business would be to postpone the matter, adhering to the organization's rules of order. This procedural action is relevant to parliamentary practice, and the Supreme Court has determined that the Senate remains in session if it declares itself as so.
Step-by-step explanation:
If a motion to 'lay on the table' is made when there is no urgent business, this is a procedural action typically meant to postpone consideration of an issue. In parliamentary practice, the chair would rule based on the organization's rules of order. If the motion is properly made according to these rules, the chair would accept it and the matter would be set aside temporarily. However, in the context provided, it seems that we're dealing with procedural actions in formal settings, such as legislative or formal meetings, which aligns more with a Social Studies understanding of governmental procedure rather than etiquette. Taking into account the excerpt regarding the pro forma session, the chair must adhere to the official rules that dictate when the Senate is considered in session. Thus, the ruling would be that the Senate remains in session if it declares itself as such, per the Supreme Court's decision.