Answer: consensus
Explanation: In simple words, it refers to the psychological phenomenon which states that the likelihood that an individual is going to perform an activity increases when he or she thinks that their potential act aligns with the willingness of others that are related to the outcomes.
In the given case, the politician is trying to persuade that majority of the voters are in his favor. This idea will generate a perception that majority are in his favor so there must be something positive in him.
Hence we can conclude that he is using consensus.