The Crazification Factor (alternatively known as the Keyes constant) is a neologism coined in 2005 by blogger John Rogers to refer to the portion of the electorate comprising the nuttiest of the wingnuts and the batshit crazy, or at least the most diehard partisans.
Rogers was writing of the 2004 Senate election in Illinois:
Barack Obama vs. Alan Keyes. Keyes was from out of state, so you can eliminate any established political base; both candidates were black, so you can factor out racism; and Keyes was plainly, obviously, completely crazy. Batshit crazy. Head-trauma crazy. But 27% of the population of Illinois voted for him. They put party identification, personal prejudice whatever ahead of rational judgement. Hell, even like 5% of Democrats voted for him. That's crazy behaviour. I think you have to assume a 27% crazification factor in any population.
Another factor in Obamas favor at the time that Rogers didn't mention is that the original Republican candidate, Jack Ryan, had been forced to suspend his candidacy after his divorce and custody records were released to the press, revealing that he had taken his former wife, actress Jeri Ryan, to various sex clubs (including, in at least one case, a bondage club) and tried to have her perform sex acts on him out in the open. Keyes was the GOPs last-minute replacement on the ticket after the sordid details of Ryans divorce came out. So not only was it a normal candidate running against a clearly crazy opponent, but the crazy guy also had the baggage of the last guys sex scandal following him, and had been drafted into the campaign with little time to prepare.
https://rationalwiki.org/wiki/Crazification_factor