One afternoon Polly tells Jerry that someone named Mr. B wants to hire the cab for the election, meaning he's looking to advertise and wants a place to put his posters. Jerry refuses, saying, "I should not like to have it pasted all over with their great bills" (42.2).
Polly asks Jerry if he'll vote for Mr. B, but Jerry says no because the guy has no clue about the wants and needs of workers. Jerry is kind of an opinionated guy, it seems.
On the day before the election, Dolly comes home crying, saying that boys have taunted her, calling her a "ragamuffin." Her brother, Harry, says he's defended her, and has "[…] given them a thrashing they will remember" (42.10).
Jerry lectures Harry, saying he hopes Harry will always defend Dolly, but that he won't tolerate any "election blackguarding" (42.13). And what's "blackguarding"? Taunting and ridicule. Jerry's basically saying no political arguments in the house.
Jerry wraps up his political lecture by saying, "An election is a very serious thing; at least it ought to be, and every man ought to vote according to his conscience, and let his neighbour do the same" (42.17).