Julia Gillard this week defeated Kevin Rudd overwhelmingly, but she shows little sign of winning the battle with herself to stop making bad mistakes. The aborted attempt to get Bob Carr into Parliament turned an opportunity into an own goal. Suddenly, everyone involved became a casualty.

Carr was embarrassed by being wooed and then unceremoniously dumped. NSW ALP secretary Sam Dastyari, who thought he'd done the right thing by identifying a high-profile figure to shoehorn into the Parliament and ministry, finds himself back in the box labelled ''faceless men''.

Stephen Smith, who opposed the proposal to make the former NSW premier the new foreign minister, looks the spoiler. If, as is expected, Smith returns to the foreign affairs job in today's reshuffle, his critics will paint him as putting his own interests first, as well as condemn him for cutting and running from the difficult Defence portfolio, where his work has only started. (If foreign affairs went to someone else, Smith would be left both without his preferred area and with the odium of blocking Carr.)

But it is Gillard who's the biggest loser. She's taken a double hit. She has not been able to carry through what she was apparently inclined to do in her reshuffle, making her look ineffective -and her blanket denials of the story have opened her to accusations of lying.

When Smith and whoever else raised objections to the Carr plan, Gillard either decided her initial enthusiasm had been misplaced, or she didn't dare to upset colleagues - especially Smith, who had stood aside (reluctantly) for Rudd after the election and so had some claim on the portfolio.

Gillard has made much of the fact that she, as leader, chooses her ministers. This was a power seized by Rudd (last week he said he had been wrong and would, if he won the ballot, restore to caucus the right to choose the frontbench). This week has shown the practical limits to Gillard exercising that power. She has talked tough but been exposed as weak.

Would Carr have been a plus to the Gillard government if the plan had come off? There are arguments on both sides. His arrival would have caused tension and made it look as if the federal party had to desperately import someone for the job. But Carr has a good name; he would have added some lustre to the federal party. He knows about foreign affairs and could have cut a figure on the international stage.

Gillard must be deeply disturbed, incidentally, at the leaking of the Carr story. She can't be sure that even the most confidential information will be secure (even worse now that Rudd can't be blamed). The Sydney Morning Herald's Phil Coorey initially reported that Labor had approached Carr - the Tuesday morning online report came around the time Carr was told by Wayne Swan that it was game off.

While the Carr affair hits Gillard's authority, the worst damage is to her credibility - her perennial vulnerability.

On Wednesday, The Australian reported that a ministerial rebellion had forced Gillard to drop an offer to make Carr foreign minister. When asked whether Carr had been offered a job, Gillard declared the story ''completely untrue''.

The story was not ''completely untrue'' - it was wrong on some points but the thrust was correct. There has been quibbling over whether Gillard made an ''offer'' to Carr, but this is partly semantic. She and Carr were discussing a proposal, about which they were both apparently keen, for him to take the job. A formal ''offer'' had to wait while she consulted colleagues. It didn't come but the earlier intention was there.

Instead of immediately providing a straightforward account of what had happened (such as ''yes, we had talks, in the end they didn't come off'') she played fast and loose with the truth.

But why? After all, there was nothing wrong with talking to Carr, an outsider but a respected Labor figure, about the foreign affairs job, whatever the result. As Anthony Albanese pointed out in a torrid parliamentary debate, the Queensland opposition is led by a man yet to win a seat in Parliament.

Gillard's all-guns-blazing response to the report was part of the new ''assertiveness'' that Simon Crean highlighted on Tuesday.

But ''assertiveness'' and ''authority'' are not the same thing. If assertiveness is not backed by authority, it not only comes across badly but can actually undermine an attempt to build authority.

Gillard has recently been extra-assertive in Parliament, with some of her answers laced with contempt for her opponents. On Wednesday, responding to a question from opposition foreign affairs spokeswoman Julie Bishop about the Carr affair, Gillard spat out the jibe: ''Whoever I select won't break into a sweat wiping the floor with her.'' Delivered without the slightest lightness of touch, the line came across as an ugly insult rather than an effective spearing.

Gillard now goes into the reshuffle, to be announced today, on the back foot - and it is a tough one to get right. She needs to promote unity as well as talent, imperatives that may clash. Signs of retribution will just add to the tensions already within the government. If Smith goes into foreign affairs, she will have to have a credible choice for defence and a convincing story about why the change is desirable. She can hardly say ''Stephen wanted his job back''.

While this reshuffle gives Gillard a chance to fix up some messes she made in December, it has also come too early for her and that limits her capacity to do things properly. She can't make the most logical changes, because she has just put people into new jobs. Thus, the best person for defence would be Greg Combet - indeed, better than keeping Smith there - but he has been in industry only since December, and it would look ludicrous to move him.

If Gillard's reshuffle is judged a dud, the ledger of the week in which she crushed Rudd will come out heavily on the negative side.

Gillard's discordant Carr Alarm