John Frederick Paxton

John Frederick Paxton was a male human in the 22nd century who led Terra Prime, a xenophobic group dedicated to forcing all extraterrestrials from Earth.

Toward this end, Paxton authorized the creation of a human-Vulcan binary clone from the DNA of Earth Starfleet officers T'Pol and Trip Tucker, as proof of the idea the human race was at risk. Paxton also plotted to commandeer the Verteron Array on Mars, and threatened to destroy Starfleet Command -- site of the negotiations for the Coalition of Planets -- if all aliens did not leave the Sol system immediately. He was eventually stopped by Captain Jonathan Archer and the crew of the Enterprise (NX-01), and taken into custody.

Paxton was an admirer of Colonel Green and his theories on the purity of the human race. However, he also used Rigelian gene therapy to treat himself for Taggart's Syndrome. 

Alternate universes
In one alternate timeline, Paxton successfully destroyed Starfleet Command, leading to a rise of isolationism on Earth lasting into the mid 23rd century.