What must customs officers have to conduct a search at an extended border?

To conduct a search at an extended border, customs officers must have reasonable certainty that the item has a nexus with the border. This requirement is rooted in the understanding that, while there are protections against unreasonable searches, there is a distinct legal standard when it comes to border enforcement.

The connection to the border signifies that customs officers are focused on items or individuals that are entering or leaving the country, which helps facilitate the enforcement of laws related to customs, immigration, and national security. This concept of a "nexus" is crucial, as it allows customs officers to operate with a reasonable understanding that their activities are related to their responsibilities in maintaining border security.

In the context of extended border searches, reasonable certainty reflects a lower standard than what might be required for searches conducted further inland or without the border context, recognizing the unique legal environment at the international boundary where the interest in security is heightened.