In Chapman v. Rahall, Judge Conrad of the W.D. Va. ruled that the United States was the sole proper defendant for the claims against West Virginia Congressman Nick Rahall for stuff he said on TV about the plaintiff, under the Federal Tort Claims Act as amended by the Westfall Act.
This outcome likely does in the plaintiff, either because of failure to exhaust administrative remedies for an FTCA claim or because of the intentional act exclusions to the liability of the United States under the FTCA.
Interesting that there was no discussion of the constitutional immunity of congressman under the U.S. Constitution's speech and debate clause. Years ago, the Supreme Court held in Hutchinson v. Proxmire, 443 U.S. 111 (1979), that the immunity under the Speech and Debate clause did not extend to statements made by Senator Proxmire in his press releases and newsletters.