Which of the following is an expressed power of the Senate?

The correct choice highlights the Senate's role in the confirmation process for key government positions and in shaping foreign policy through treaty approval. The Constitution specifically grants the Senate the authority to advise and consent on presidential appointments, which includes cabinet members, Supreme Court justices, and other significant federal officials. Additionally, the Senate has the power to ratify treaties with foreign nations, requiring a two-thirds majority vote for approval. This power reflects the Senate's pivotal role in maintaining checks and balances within the government and in controlling foreign affairs.

The other options relate to different branches or powers within the government; declaring war is primarily a power of Congress as a whole, issuing executive orders is an authority of the President, and regulating interstate commerce falls under the purview of Congress, but is more specifically associated with the House of Representatives.