One exasperated Labor MP told me this morning to see Labor's leadership battle was akin to watching an ugly, messy divorce. Everything built over the years by Kevin Rudd and Julia Gillard since 2006 is being torn apart.

The children — the ALP members — are the innocents caught in this spat. The house sold off, furniture divided, and on and on.

For all the sniping in the shadows over the past few weeks and months, the public can no longer doubt the level anger between these former partners.

Rudd has set himself as the victim. It's a ''soap opera'', he says, and ''I won't be part of it'' for the good of the nation. The truth is undoubtedly more complex.

Rudd appears to want vindication, for the history books to record that the Labor party wronged him in 2010.

There is no great policy issue at stake here — this is entirely about personality, the bitterness of separation.

The other man in this picture, Tony Abbott, is almost an afterthought, although Rudd has cleverly raised the spectre of an Abbott government to focus Labor minds.

Gillard will now have to defend the role played by her supporters, such as Simon Crean, as being seen to drive him out.

What is hardest in any divorce is it forces the family to chose sides. Some in the caucus — though none with a marginal seat — would prefer to simply go to an election to have the people judge the party, and from there rebuild.

A Keating-style two stage challenge seems unlikely to work for Rudd. This is his best shot to return to the top job. Rudd on the backbench can't strut the international stage, meeting powerful people and commanding an audience.

Otherwise, he will simply become ''the ex''.

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