Cougar, how much moderating are you doing compared with the other moderators? Are you doing a lot more than your ‘fair share’?
If so, whether it’s because you are good at it, because you enjoy it/like spending time on the forum, or because the other moderators are either happy to take a back seat while you are so active or don’t feel able to take up more of the workload (i.e. they don’t want to tread on your toes or appear to push you out), then maybe you do need to step back and encourage the others to be more active (in the same way a manager has to learn to stop doing too much and delegate more). Maybe pass the responsibility for some specific threads, like the Referendum, to other moderators.
TJ’s suggestion of a lower threshold for (shorter) bans also sounds like a good idea, i.e. akin to zero tolerance policies which aim to tackle anti-social activity at an early stage/low level, with increasing penalties for non-compliance (first ban of one week, second ban within 3 or 6 months of two weeks, third ban of four weeks etc.). You need forum users to self-censor, and it may only be the imminent prospect of a ban which makes users think a bit more carefully about their posts.