If the county Sheriff doesn’t consent, Federal Law Enforcement can not operate in the county. He is the final arbiter, period.
The FBI has authority to investigate threats to national security pursuant to presidential executive orders, attorney general authorities, and various statutory sources. Title II of the Intelligence Reform and Terrorism Prevention Act of 2004, Public Law 108-458, 118 Stat. 3638, outlines FBI intelligence authorities, as does Executive Order 12333; 50 U.S.C. 401 et seq.; 50 U.S.C. 1801 et seq.
The FBI could also be operating under this administration’s corrupt practices using laws like the above for protection or reason for their actions in a state. FJB and Mullet Garland have called us threats to national security as a way to subvert the state’s responsibilities in these matters. That said the Sheriffs in the counties, where these type of arrests have happened, need to be voted out of office for not standing up for their boss, the citizens of their counties. As the case shows, despite the support MAGA gives to law enforcement there are many in law enforcement who bend the knee to whoever pays them not to the voters.
People DO NOT understand the power of Sheriffs. Heck, I think some Sheriffs don't understand the power they have.