So… what exactly is a spill?

We’re all talking about it, but what exactly happens at a leadership spill?

At 10am on Monday morning, Julia Gillard will call a ‘spill’ or a ‘leadership ballot’ at a special caucus meeting.

All 103 members of the Labor caucus – all Federal Labor MPs and Senators will decide at that meeting if they should take a vote on who should lead the party.

At the spill, Julia Gillard will step aside from the PM position leaving it open to anyone who wants to put his or her hand up for the role.  She’s already indicated that she will be re-contesting for the role.

Anyone can nominate. But this spill has been called for one person only. Mr Kevin Rudd. Kevin 07. Kevin 747. Ex-Prime Minister of Australia. Ex-Foreign Minister of Australia. Ex-Happy Little Vegemite.

He wants the job, and Julia Gillard is forcing him to finally fight for it.  Put up or shut up.

To win, he’ll need 52 out of the 103 votes. It’s looking extremely unlikely that he’ll get that many votes. In 2010 he didn’t even contest the spill because he knew he wouldn’t win.

But when he lands in Australia tomorrow, he’ll hit the phones like a telemarketer working on commission. “Hello sir, are you happy with your current Prime Minister?”

Cabinet members have been pretty public in their vicious condemnation of Kevin Rudd, so if he was successful; he’d need a whole new front bench. Don’t underestimate the desire of some of those backbenchers to get a seat at the Cabinet table. His offer of a cushy portfolio could be enough to turn the staunchest Gillard supporter.

Choose your own adventure….

1. Kevin Rudd chooses not to contest the Prime Ministership. This is actually very likely, and probably a smart move. He won’t win. He doesn’t have enough time to work on the caucus members. He would prefer to call for a spill in a few weeks time. So he might sit back and quietly plot the spill on his own timetable.

2. Kevin Rudd contests and loses the ballot. He may feel like he’s been pushed into a corner and has no choice but to contest. If he fails to reach 52 votes, he will go to the backbench and quietly simmer in his rage. Julia Gillard will continue to be Prime Minister.

3. It won’t be the end though. He will contest again after he’s had enough time to campaign inside the party. Paul Keating lost his first spill against Bob Hawke…but waited and called for a second spill, which he won when Bob Hawke stood down. Julia Gillard has given a commitment that if she were to lose, she’ll move to the backbench and never contest again. She asked Rudd to give the same commitment. He won’t.

4. Kevin Rudd wins. He is our Prime Minister again. Julia Gillard moves to the back bench. The bile created from all the nastiness and betrayal will start to poison the Labor party…. Nobody wins.

5. Simon Crean also puts his hand up for the leadership….. everyone slaps their foreheads and has a little cry.

Lauren Dubois is Mamamia’s Canberra-based political contributor. You can follow her on Twitter here