Somebody who knows Julia Gillard well and works closely with her once remarked that her greatest attribute was her outward calm.
"You wouldn't know whether she had just declared war or won the lottery," he said.
Two weeks ago, while Gillard was in Singapore and Turkey and while the Peter Slipper affair was raging at home and the pressure on the government and Gillard's leadership was building, she kept her calm demeanour at all times. Not once did she show signs of the enormous strain, be it publicly or internally with staff.
On her return home, a few cracks began to show. During the press conference in which she announced the sidelining of Slipper and Craig Thomson, she at times became snippy and aimed a few gibes at journalists.
But, overall, Gillard's signature strength throughout her time at the helm has been just that - strength.
Kevin Rudd, the man she replaced, could not cope with unpopularity. It ruined him. When Rudd knocked off Kim Beazley for the leadership in December 2006, he was an immediate hit in the polls. He outranked John Howard all the way until the November 2007 election at which he became prime minister.
After that, his poll ratings - both personally and those of the government - stayed in the stratosphere. They were at levels that were always going to be unsustainable and caused concern about what would happen when they inevitably fell.
When Tony Abbott replaced Malcolm Turnbull as Coalition leader in December 2009, and soon after Rudd's climate change dream became a nightmare with the collapse of the Copenhagen conference, reality kicked in. Rudd, according to those close to him, could not cope.
As the polls began to tighten and the hard work of government became apparent, Rudd became increasingly erratic and unable to make decisions.
At first, people made excuses for him. "Kevin's just learning to be unpopular," said one of his ministers at the time. But when the government ditched the emissions trading scheme in April 2010 and the polls went into freefall, faith in Rudd evaporated.
According to one of the key players in Rudd's June 2010 removal, it wasn't the fact Labor had plummeted in the polls that was the problem, it was the stark realisation among colleagues that Rudd had no ability to get the government out of the slump. "He wouldn't listen to anybody, he wouldn't make a decision."
Whether it was the right or wrong thing to do, Gillard replaced Rudd.
When Rudd was running for the leadership two months ago, one ardent Gillard supporter said people should consider just how Rudd would have fared under the constant pressure Gillard had faced since she took the leadership.
This has included an election campaign destroyed by leaking, negotiating a minority government with a grab bag of Greens and independents and negotiating and implementing a carbon price, and all in the face of diabolical opinion polls, leadership speculation, a hostile media and constant haranguing by a tenacious Abbott.
"She has been swimming upstream in a river of shit for 18 months with her mouth open, and she's still smiling," the supporter said. "Rudd would have drowned long ago."
Gillard's strength and toughness have got her this far and those who once thought she would be the kind to tap the mat should she realise she could not lead Labor to victory, are rethinking.
Gillard shows no sign of conceding. On Thursday, she mocked the timelines that keep being set for her leadership.
Since the middle of last year, people out to depose the Prime Minister have set various deadlines, ranging from the visit of US President Barack Obama, the ALP National Conference in December and Christmas, to the Queensland election in March.
Now, anxious MPs are suggesting a move by the end of June should the budget fall flat.
"Clearly, over the past few days there are stories about deadlines and all of that kind of thing," Gillard said. "If I was someone given to keeping newspaper clippings, I'd have filing cabinets overstuffed and toppling over with stories written about deadlines.
"So you'll have to excuse me if that's not my focus. My focus is getting on with the job in the nation's interests."
If her colleagues want to change leaders, they will have to blast her out.
Gillard can be as calm and resolute as she likes. If the grudging respect this generates does not translate into a lift in the polls, her MPs do not plan to go to an election on a primary vote at or about 30 per cent.