“Our number one risk at this point is the federal government,” Colorado Secretary of State Jena Griswold said. She said concerns about federal interference in election administration mean federal officials will not be welcome inside the Cyber Command Center, which the Colorado National Guard establishes each election to help protect voting infrastructure from cyber threats.

States and local governments have spent years preparing for risks including bomb threats at polling places, large-scale disinformation campaigns and hacking efforts backed by foreign governments. Election officials from both parties say strained relations with Washington have added a new challenge to those preparations.

The Constitution gives states primary responsibility for running elections. But the Trump administration has spent much of the past two years seeking changes to the U.S. election system and voter registration, raising concerns among state officials about the federal government’s role.

Colorado was among 15 states that the Department of Homeland Security reportedly flagged this summer for monitoring over potential vulnerabilities in election integrity, according to a report cited in coverage of the issue.

The dispute presents a practical concern for local election offices: cybersecurity threats can cross state lines, while election administration remains largely in state hands. Colorado’s decision to bar federal officials from its command center underscores how political mistrust could complicate coordination as officials work to secure voting systems and reassure voters ahead of the midterms.