(Image: Mitchell Squire/Private Media)

If North Sydney MP Trent Zimmerman is lucky, a large proportion of the voters in the NSW state seat of Willoughby will have made up their minds before last week's shambolic events in Parliament over religious discrimination, in which Zimmerman was one of several "moderate" Liberals to cross the floor and defeat an effort to enshrine discrimination against trans kids.

If not, it's no wonder the Liberals are polling his seat frenetically. Willoughby delivered an 18% swing against the Liberals, almost all of it to independent Larissa Penn.

Some specific factors are relevant: the loss of Gladys Berejiklian's personal vote would have been significant. And in Tim James, the Liberals -- or more accurately the preselectors of Willoughby -- put up a wholly inappropriate figure: a doctrinaire right-wing male factional operator straight from the business-as-usual playbook that has seen the Liberals' north shore heartland increasingly look at small-l liberal independents.