Although the real strength of his support in the caucus remains uncertain, there is no sign yet that key ministers are about to desert the Prime Minister - although given the volatility and desperation of the parliamentary party nothing can be ruled out.
But support for a Rudd leadership has grown among backbenchers and unions have shown a new ambivalence. The Australian Workers Union, a key support base for Gillard, has emailed its members asking for their views on the leadership and the umbrella Council of Trade Unions has said that while it was "supportive" of Gillard the leadership was a matter for the caucus.
If Rudd was to challenge and lose, he would be finished for good. And if he did win, there is no guarantee he would produce the kind of miracle predicted by opinion polls and haul Labor back within range of victory.
There is widespread feeling that voters hold Labor in such contempt that it will be decimated in September whoever is at the helm.
At best, Rudd could possibly hold losses to a level that would allow Labor to rebuild rather than spend possibly more than a decade in the wilderness.
Even if he does not challenge, Rudd's choices are limited. Any bid for leadership after the predicted landslide and what would be Gillard's inevitable departure would be deeply scarred by the fury and contempt of many MPs who regard his long-running - if often subterranean - campaign to return to power as treachery that killed the Government through destabilisation.
Rudd was never popular within the parliamentary party and his role in the probable ascension of Opposition Leader Tony Abbott would never allow him to bring unity to what would be a bitter, vengeful remnant. As it is, if Rudd wants the leadership now he must decide without delay to risk a bloodbath.
Gillard yesterday repeated her determination to stay, saying she had the numbers in caucus and that she would not be swayed by a tap on the shoulder - which senior ministers have adamantly declared will not happen.
"I'm getting on with the job, the things that really matter," she said.
But although some senior supporters say there is no need for a new ballot, others, including Climate Change and Industry Minister Greg Combet and Trade Minister Craig Emerson want a vote to put an end to speculation.
"We cannot leave this week as a disunited party," Emerson said.
A Newspoll in the Australian yesterday underscored the party's plight, finding that Labor's primary vote had fallen below 30 per cent and that Abbott's lead as preferred prime minister had increased to 12 per cent.