Definition: The action of a state whereby its sovereignty is placed between its citizens and the federal government. ~~Miriam-Webster.com
It is the right and the duty of any state to interpose for its citizens whenever the federal govt acts outside the powers delegated it in the Constitution
Interposition is required by the state of Montana, standing between the citizens of Montana and such unlawful federal activities—e.g., the determination to arrest and prosecute federal agents who illegally defy Montana’s nullifications
County governments and Constitutional sherriffs also have the right, authority and duty to interpose in such cases to protect their citizens from illigitimate federal action.