Tweeting who to vote for at a by-election on the day the poll is being held is silly, but it isn't exactly the worst thing that any politician has ever done. Hell, it may not even be illegal.
So the whole David Cunliffe storm-in-a-Twitter-cup thing needs settled. Here's how I see it.
First of all, he was dumb to send out the tweet. Especially if, as I understand it, the Electoral Commission specifically warned candidates and parties not to tweet on the polling day. Sometimes you just need to put the phone down and walk away.