Thomas Eckhart survived the conflict in the congressional bunker in West Virginia. With contact lost with Control Station ENCLAVE and Enclave leadership due to a damaged communications array, Eckhart assumed control of the Enclave forces at the congressional bunker and manipulated automated voting systems in Appalachia to make himself the nominal President of the United States from 2083 until his death in 2086.
Eckhart's obsessive focus on eradicating communism caused him to make increasingly unethical decisions for the sake of accumulating power and raising the DEFCON level to activate Appalachia's dormant automated nuclear silos, resulting in his own soldiers revolting and imprisoning him. He and all other human inhabitants of the congressional bunker suffocated to death in 2086, after MODUS released a toxin into the air circulation system in retaliation for the rebelling soldiers attempting to destroy its databanks.
Thomas Eckhart is mentioned only in Fallout 76.