As long as the Australian Workers Union stain lingers and/or grows, Labor cannot hope to win an election next September, let alone a snap poll that Prime Minister Tony Abbott may well call to capitalise on the Shorten malaise. Last week Fairfax Media identified tens of thousands of dollars of largely unexplained employer payments to the AWU's Victorian branch from January 2004 to late 2007. Mr Shorten was state secretary from 1998 and federal secretary from 2001 to 2007. Mr Shorten called the reports "an unfair smear". They were not. They reflected legitimate investigations into a man asking voters to trust him. The latest revelations are even more damning. The fine print in documents lodged with the Australian Electoral Commission and AWU bank records show the giant builder Thiess John Holland paid Mr Shorten's union nearly $300,000 after he struck a landmark workplace deal that saved the company as much as $100 million on the Melbourne Eastlink tollway project.

The deal was hugely favourable to the employer, just like other deals struck by the AWU during Mr Shorten's reign. Some deals involved payments to the AWU, or the payment of member's dues. The AWU struck agreements with companies when it suited the union's political purpose, which was to bolster membership. This allowed the AWU to assert its dominance over rival unions and bolster the power of its leaders in the Labor party's corrupted, undemocratic structure. Mr Shorten has described as completely unfair and false any implications that he is not completely motivated and committed to getting a better deal for workers, for productive relations at companies and for standing up for people. But voters are entitled to examine the totality of Mr Shorten's time at the AWU and wonder whether the people for whom he stands are those who can first and foremost help him further his political ambitions. Voters will also assess the claims in light of Mr Shorten's eight years in Federal Parliament. The latest revelations came as his role in removing two prime ministers, Kevin Rudd and Julia Gillard, returned to the nation's television screens in the ABC series The Killing Season. Mr Shorten harnessed union support to gain preselection for the Melbourne seat of Maribyrnong in 2007. Mr Melhem also made a $2000 donation through his Industry 2020 slush fund to Mr Shorten's campaign to keep Maribyrnong in 2009.

Mr Shorten's 52-48 victory over Anthony Albanese in the national Labor leadership ballot in October 2013 remains tarred by 73 changes to the addresses of branch members in Auburn in western Sydney. Despite his claims to have zero tolerance of corruption in Labor, Mr Shorten has done too little to reform the party structure, which delivers unions like the AWU disproportionate influence and operates on dirty factional deals. Mr Shorten could shrug some of this off if voters had warmed to him. While the Labor leader in person is a smart and charismatic man with good ideas, he remains approved by only 41 per cent of voters, the Fairfax-Ipsos poll says. The latest revelations over his AWU past also came a day after he had been caught out playing bad politics, as the Greens and the government compromised on pension reform. The coming days will determine whether Mr Shorten, the ultimate political operative, can find the numbers to survive. The damage being done in the meantime is a big price for voters and Labor to pay.