Which statute specifies the protocol for conducting board searches of vessels?

The correct answer, 19 USC § 1581, outlines the procedures and authority related to customs officers conducting searches of vessels. This statute specifically grants customs officials the right to board and inspect any vessel arriving in the United States to enforce customs laws. The focus of this section is on facilitating customs enforcement, which includes verifying compliance with regulations and ensuring that no illegal goods are smuggled into the country.

In contrast, the other options pertain to different areas of law or specific provisions that do not address vessel searches. For example, 19 USC § 1595(b) deals with penalties regarding violations of customs laws, and the INA sections pertain to immigration enforcement rather than customs and vessel inspections. By clearly defining the authority of customs officers in the context of vessel searches, 19 USC § 1581 is the relevant statute for this protocol.