- "Ladies and gentlemen, the truth is that mutants are very real, and that they are among us. We must know who they are, and above all, what they can do!"
- ―Senator Kelly
Robert Kelly was a United States senator who advocated for the implementation of the Mutant Registration Act. He was turned into a mutate by a machine operated by Magneto, but subsequently died from his unstable mutation.
Robert Kelly was a U.S. Senator and a major proponent of the Mutant Registration Act. He was captured by Mystique (impersonating his aide Henry Gyrich) and Toad (disguised as his helicopter pilot) and taken to Genosha as a prisoner. There, he was transformed into a mutant by Magneto's Conversion Machine.
Using his new-found abilities, Kelly escaped Genosha and eventually arrived at the X-Mansion to receive help. However, the unnatural mutation created by the radiation of Magneto's machine caused his cellular structure to break down. He later disintegrated into water and was last seen alive by Storm.
Mystique survives her injury from Wolverine at Liberty Island and impersonates Senator Kelly in order to call off the Mutant Registration Act. The X-Men notice her impersonation as Senator Kelly on TV.
Kelly, now impersonated by Mystique, gives others the impression that he is now more supportive of mutant rights.
- Elasticity: Once turned into a Mutate Kelly was shown to possess the ability to stretch his body, and was able to use this to escape Magneto's prison. The full extent of this ability was not known. It was shown, however, that he could not apply this ability to his clothing, as when he fell from Sabertooth's grasp, he fell through the holes in his clothing.
- Aquatic Adaptability: Kelly seemed to possess some sort of adaptability mutation. This was only displayed briefly, but was shown when he first stepped out of the ocean after a night of drifting, small slits in his back disappeared. These were implied to be gills that helped Kelly to breathe when under the water's surface. If this mutation is similar to that of Darwin's has not been answered.
- Cyclops † - Ally
- Henry Gyrich † - Assistant
- Jean Grey † - Enemy turned Ally
- Professor X - Ally
- Storm † - Ally
- Wolverine - Ally
- During the U.S. Senate scene in X-Men, Kelly's desk sign indicates he represents the state of Kansas.
- In a television special to promote the X-Men movie, which also served as a mini-sequel to it, Bruce Davison reprised the role of Senator Kelly, giving a press conference at which his young daughter begins to act strangely, and just as he is winding up his speech, she is revealed to be a mutant.