Victorian upper house MP and Australian Workers Union powerbroker Cesar Melhem has written to the Socialist Left faction to tell it who to vote for at a crucial meeting of the party’s Public Office selection committee tomorrow night.

In a letter sent yesterday to Socialist Left faction secretary Andrew Giles and obtained by Crikey, Melhem outlines his faction’s stance ahead of the showdown that will select Labor’s candidate for David Feeney’s vacant Senate spot and the candidate for the plum lower house seat of Hotham. He says the Unity caucus has endorsed disability worker Rosemary Barker ahead of Geoff Lake in Hotham, and Hospital Workers Union manager Kimberley Kitching ahead of Stephen Conroy loyalist Mehmet Tillem in the Senate.

Melhem is aligned with Bill Shorten and relations between the two senior Labor MPs are believed to be at breaking point. He claims Kitching has the support of 18 out of Unity’s 25 POSC delegates and that the Unity caucus would move to formally anoint her at 4pm tomorrow. Under a 2009 “stability pact” with the SL designed to stem the tide of preselection bloodshed, the SL would then add its 37 members to the vote, leading to an absolute majority and a six-month Kitching stint on the Senate’s red leather. She would also appear on the Victorian Senate ticket in the probably still unwinnable number 3 “death spot”.

However, Crikey understands Melhem’s numbers are hotly disputed and that there is a huge amount of water still to flow under the bridge between now and tomorrow night, with furious mobile calls being made to shift the balance in Tillem’s favour. Crikey revealed the looming stoush on Friday night.

In his forthright letter to Giles, the plain-speaking member for Western Metropolitan explains the situation thusly:

“The Labor Unity group has entered into in an agreement with the Socialist Left for the stability of the party and the selection of candidates to make a positive contribution to the good government of Victoria and Australia. This agreement is widely-known as ‘the Stability Deal’. Pursuant to processes well-established within Labor Unity (Short/Con) we have agreed to endorse Rosemary Barker – our only candidate in the Hotham preselection – and will ratify that decision at the meeting of our POSC caucus on Tuesday evening.

“Further, the Labor Unity Executive agreed that we will only support members of the Labor Unity group for the Senate vacancy and that the decision — in the event of a contest — would be made by a majority of Labor Unity POSC members, and would be a binding decision. At the close of nominations, Kimberley Kitching and Mehmet Tillem nominated. I am writing to inform you that Ms Kitching has provided me with the written pledges of support of 18 of our 25 POSC delegates.

“Should there be any doubt, these can be provided to you. Accordingly, I expect Ms Kitching will be ratified as the Labor Unity candidate at our POSC caucus on Tuesday at 4pm, or should Mehmet receive a majority support he will be the endorsed candidate…in other words whoever gets the Majority vote will deemed to be the LU candidate in line with our agreement as this seat is allocated to the LU — the same as the other 2 seats [for] which the Executive have endorsed Rosemary for Hotham and Joanne Ryan for Lalor.”

The AWU has eight votes on the 100-member POSC, the usually supportive Plumbers Union and the Asmar crew on five along with two frequently side-changing delegates from the Suleyman clan. The Melbourne Ports federal electorate area has two, with Russell Atwood from the ASU somewhere in the middle and Conroy seven for a grand total of 25. The “ShortCons” are normally inseparable, but Tillem’s nomination has exposed internal ruptures that have left Left observers entertained and incredulous in equal measure.

Giles declined to comment this afternoon.