Herbert Hoffman filed a federal court complaint today aimed at preserving his spot on the Nov. 4 election ballot as an independent candidate for U.S. Senate.

The U.S. District Court filing includes a request for a temporary restraining order and a preliminary injunction seeking quick action before ballots are printed.

In addition to Hoffman, a retired psychologist from Ogunquit, the plaintiffs include 13 registered Maine voters who signed petitions for his name to be listed on the November ballot.

John Branson, the Portland lawyer representing Hoffman, said the plaintiffs believe their constitutional rights to freedom of political expression and due process were violated by a Maine Supreme Judicial Court interpretation of state election law.

The state court overturned decisions by the Secretary of State and the Maine Superior Court last month when it ruled that Hoffman should not be listed on the ballot because some of the signatures he collected on his nominating petitions were invalid.

Hoffman is running against incumbent Sen. Susan Collins, a Republican, and her Democratic challenger, U.S. Rep. Tom Allen.

Democrats challenged the petitions with the Secretary of State, and later in court, because they are concerned that Hoffman will take votes away from Allen in what may be a close race.

Hoffman asked the U.S. Supreme Court to delay the Maine Supreme Judicial Court's decision on the petitions, but the federal court rejected that request last week.