"I like him, but Michael Foot can't win an election." "Why?" "Not enough people will support him." "So support him." "I can't." "Why?" "Because he can't win." This conversation didn't take place often enough in 1980, and the Labour Party were out of power for 18 years...https://twitter.com/DSilvermint/status/1124455232228880385 …
-
It looks like bad reasoning on the face of it because it has a hidden assumption, viz. that most of the other people are not supporting the candidate for the same reason. But if it’s not true, if most other people have different reasons, then the reasoning is fine.
Even if it is true that a politician is unelectable just because they are perceived to be unelectable (and normally it will be for other reasons) that's still a political reality with which you've got to reckon.