The Liberal Party has just preselected Greg Smith over Pru Goward to be its candidate for the state seat of Epping in the upcoming NSW election. The NSW Liberal Party preselects its candidates using a panel of representatives from the local branches rather than the local members voting directly or there being some combination of local voters and central executive committee votes.
Branch stacking has been part of both major political parties, especially when the goal is to preselect a particular candidate. It seems to me that it’s preferable for local members to directly vote in preselections – there’s no need for an intermediary panel when the number of local members is fairly small (at most hundreds). Having an intermediary panel allows local member’s preferences to be distorted.