Let’s cut to the chase: whatever the optimists in the ALP may imagine, there is almost no chance of Kristina Keneally beating John Alexander in the Bennelong byelection.

Keneally is a well-known, serious, sensible, convincing and personable politician and under normal circumstances would be an ideal candidate for a marginal seat in a normal byelection – the kind of byelection in which the incumbent declares that he has to desert his constituents because he needs to spend more time with his family, whether he has one or not.

But these are not normal circumstances – the long-running debacle over dual citizenship has left the voters confused and resentful. However, they are not likely to take their anger out on Alexander, nor for that matter on Barnaby Joyce, whom they regard as dinkum Aussies, whatever the bloody High Court might think. True, Alexander’s very belated admission of his ignorance over his ancestry was more than somewhat negligent, but what the hell – the man played tennis for Australia, so most, if not all, can be forgiven.

There will certainly be a swing against him, but it should be less than the almost 10% buffer he had at the last election. The swing will be the fault of the very unpopular government he represents, and as long as it is not about him, there should be very little to worry about.

Very little, but enough to spook a prime minister and his troops into precisely the wrong strategy – a ferocious smear against Keneally’s past, rather than an endorsement of Alexander’s future.

As New South Wales premier, Keneally was given a hospital pass by a demoralised party long past its political use-by date and she was supported by some very unsavoury characters in the process. But the worst that can be thrown against her is naivety; indeed, the Independent Commission Against Corruption, which was eviscerating Eddie Obeid, Joe Tripodi and Ian Macdonald, actually sent her a herogram.

For Malcolm Turnbull, Julie Bishop and the rest of the gang (who, let’s face it, have some pretty unloveable characters among their own troops) to leap into the cesspool looks more desperate than statesmanlike. In the present febrile atmosphere it risks a backlash that just might push Keneally over the line.

Highly unlikely, as I have said, but at the very least her candidature will be yet another distraction for a prime minister who has had quite enough of them in a year he would like to forget as soon as possible. On that level alone it has to be called a win for Bill Shorten and Labor.

The history of attempts, by all parties, to install star candidates is a mixed one; there have been some successes, albeit often short lived, but there have been some spectacular crashes and burns. But then there is one moment that Labor will never forget: the glorious victory in Bennelong itself in 2007, when Maxine McKew prevailed over the incumbent prime minister John Howard, and her supporters flashed the message through to party HQ: “Fully flushed!”

Shorten would love to have a reprise of that result. He probably won’t get it. But he and Keneally have already given Turnbull an awful fright, so the idea was worthwhile anyway.