Unfortunately Union endorsement does not always translate into members votes.
In 2008, Geoff Southern ran as a Senatorial candidate, and despite Union endorsement, with a recommendation that members get out and vote for Mr Southern, the result was paltry - it was clear that either members could not be bothered to vote, or they had decided to vote for other candidates than Mr Southern.
One part of the paradox is that there are working class people who will vote for "the establishment", just as in the UK, working class people (certainly in the past) voted Conservative. The fictional Alf Garnet, who was a working class Tory bigot, was created by Johnny Speight partly drawing from his own experiences of such people.
They will elect people whom they see as having, for example, a sound economic strategy rather than one that does not look credible, and these are the people who won't support Geoff Southern.
That's not saying that either there is a "sound economic strategy" or that the one promoted by the Unions and Mr Southern would not work - I'm personally suspicious of both - but it is a matter of perception, and people vote based on perceptions rather than what may be the case - management speak usually trumps class war speak (which is why one politician uses words like "efficiency" and "comprehensive spending review", but gives very little a way about the fine detail of said review).
