A conservative legal group has filed suit against Department of Homeland Security (DHS) Secretary Janet Napolitano and Attorney General Eric HolderEric Himpton HolderTrump rebukes Holder, Clinton with 'jobs not mobs' refrain Eric Trump calls out Holder on kicking comments: 'Who says this?' Two Minnesota Republicans report attacks MORE over the DHS memo warning of the threat from "right wing extremists."

The Ann Arbor, Mich.-based Thomas More Law Center said the policy reported this week targets certain individuals and groups for disfavored treatment based on their opinions on political issues.

The suit, filed on behalf of radio talk show host Michael Savage and the anti-abortion group Center for Bio-Ethical Reform, seeks a permanent injunction against the policies outlined in the memo, as well as attorneys' fees.

"The [policy] is a governmental attack on the reputations of Plaintiffs that is designed to marginalize them and their opposition to the policies and the practices of the federal government, particularly including their opposition to the policies and practices of the Obama administration," attorneys wrote in the filing.

The suit, seen here, was filed in southeast Michigan's federal court.