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Just a note for those wondering at the whimpering of certain political figures over canceled book contracts: Many publishers now routinely insert morality clauses in author contracts. (see this article for a good background: https://www.sidebarsaturdays.com/2018/09/08/https-wp-me-p7vddb-cf/ )
Authors' groups have been disapproving of these for a good while now. (See this posting from the Authors' Guild on the subject.) https://www.authorsguild.org/industry-advocacy/why-we-oppose-morals-clauses-in-book-contracts/
...With this in mind, a knowledgeable author watches out for such clauses and seeks their removal. (Or their agent does.) This may or may not be possible... at which point, as regards the pros and cons of signing that contract, the issue's in the author's/agent's court.
It's possible that the politician in question may have signed such a contract due to (a) not being knowledgeable enough to refuse, or to get the clause removed, or (b) not being able to even *imagine* a situation in which such a clause would ever have been invoked against *them.*
In which case... they're just going to have to suck it up. 
