What is one non-legislative power of Congress?

A non-legislative power of Congress refers to abilities that do not involve making laws but are essential for the functioning of government and the balance of powers. Confirming presidential appointments is one such power, as it allows the Senate to provide advice and consent on key positions in the executive branch and the judiciary. This role serves as a check on the president's power to appoint individuals, ensuring that qualified and acceptable candidates are chosen for important government roles. This process underscores the system of checks and balances integral to the United States government by requiring collaboration between branches.

In contrast, the other options represent legislative powers. Collecting taxes and regulating commerce are directly tied to Congress's role in law-making, and declaring war, while a significant power, is part of legislative authority concerning military engagement decisions.