Under what circumstances can a private citizen be deemed an instrument of the government?

A private citizen can be deemed an instrument of the government when they act in a way that involves government knowledge or involvement in their activities. In this case, if the private citizen is aware that the government is aware of their actions, it creates an implication of partnership or cooperation with the state. This relationship can make their actions subject to the same constitutional constraints that apply to government officials, particularly regarding the Fourth Amendment, which protects against unreasonable searches and seizures.

When assessing the role of private citizens in relation to government action, courts look for signs of collaboration or endorsement from government entities. If a private citizen acts with the understanding that their actions align with governmental interests or that the government has given tacit approval or at least knowledge of their actions, they can be classified as operating as an agent of the government. This is significant because it can trigger constitutional protections and scrutiny that would not apply to their conduct in the absence of such governmental involvement.