A political decoy is a person employed to impersonate a politician, to draw attention away from the real person or to take risks on that person's behalf. This can also apply to military figures, or civilians impersonated for political or espionage purposes.
The political decoy is an individual who has been selected because of a strong physical resemblance to the person being impersonated. This resemblance can be strengthened by plastic surgery. Often, such decoys are trained to speak and behave like the "target".