Immediately, Gillard needs to circle the wagons, ensure her troops have their guns pointed outwards rather than at each other, and try to restore some sense of unity, purpose and strength. No easy task.
The spill precipitated by the frustrations of Simon Crean - a lifelong unionist and Labor loyalist who was a senior minister through the heady Hawke-Keating years - took almost everyone by surprise. So did Rudd's decision not to stand against Gillard.
Rudd was ousted by Gillard, a former supporter, in a 2010 coup. His supporters waged a constant war of attrition, undermining Gillard at every opportunity, and trying to lure MPs to their camp.
Rudd yesterday confirmed he would not stand, ever again, for the leadership, killing what small shreds of hope remained among supporters of a comeback. Most are realists: no resurrection is possible, and any efforts to promote one would evaporate whatever tiny chance Labor has of retaining power on September 14.
Gillard is now clearing the decks. Key Rudd backers have been exiled to the back benches. They include Crean, without a portfolio or shadow ministry for the first time in his 33-year career, Cabinet ministers Martin Ferguson and Chris Bowen, and three Government whips.
Her game plan now will be to regroup, regain control of the political agenda from Opposition leader Tony Abbott, and turn the heat on Abbott over his policy and campaign promises.
But Abbott is a formidable agenda-grabber, focusing on a narrow band of core Labor vulnerabilities. He will not let the Rudd turmoil die, capitalising on wide voter perceptions that Labor has lost the plot and remains "paralysed ... by its own civil war".
He intends putting a no-confidence vote to Parliament when it resumes for the Budget session in May.
Behind this the Government is struggling under other burdens, not all of them unique to Labor or even Australia, but nonetheless pointing to a party that has lost its way.
Some are directly Gillard's fault. Labor has managed a low-inflation, low-unemployment, expanding economy through the worst of the world's turmoils. She has allowed the message to be lost. She has also introduced significant policies ranging from health, education and welfare to national management of the gravely endangered Murray Darling river system. Again, missing in action.
Good policy has at times been abandoned for short-term political gain. She backflipped on a carbon tax, bungled the mining tax, failed to find or implement other measures, and lost credibility by insisting repeatedly that she would produce a Budget surplus when it was clear to all that it would be either impossible or destructive.
She lost further mana by failing to find adequate policies on asylum seekers, restoring instead much of former Prime Minister John Howard's reviled Pacific Solution. Most recently, efforts at media reform collapsed into chaos.
Labor has also resorted to class and gender warfare.
But there are other, fundamental, problems. Since the wildly reformist days of former Prime Ministers Bob Hawke and Paul Keating, when everyone knew what Labor stood for, the party has wallowed. It cast about for saviours, chewing through Kim Beazley, Crean, Mark Latham, Rudd, and now Gillard.
Its core branch membership has been plummeting, reflecting a wider swing away from politics and volunteering among Australians. Branches mainly survive on baby-boomers, with too little new blood coming through.
Funding has increasingly been a problem. So have unions, Labor's traditional power base and breeding ground for new leaders: membership has dived as more young Australians take up contract work outside the award system, or set up their own businesses.
Affluence has changed the suburbs. Class warfare no longer has relevance.
A party review of its problems concluded that Labor had lost its identity, with no clear direction.
Its passion for ideas has melted into a centre field not vastly different from its opponents.
And it is operating in an entirely new environment. The voracious 24-hour news cycle, enhanced by the internet and social media, has exposed Labor to pressures not felt by any previous Government.
Crean was right when he said on Thursday that Labor's problems went far beyond just the leadership and that voters needed to believe the party had conviction, believed in what it stood for, and had a coherent message it was determined to pursue: a big, big call for Gillard over the next six months.
