Craig Thomson has set a few Coalition supporters' hearts a flutter this week - and caused Labor supporters to think about their mortality.

Thomson's marginal seat of Dobell in NSW would fall with a swing of 5 per cent. The Liberals held it before the Rudd election in 2007.

If he was forced from politics, then almost certainly the 90,000 electors in the Central Coast seat would decide the Government's fate in what would be an incredible by-election.

As it stands, that's all a bit of a stretch. Only opposition MPs are talking about criminal behaviour. The NSW police aren't even investigating the allegations against him.

But issues like these can nevertheless take on a life of their own, with minor transgressions compounded by subsequent poor decision making.

The facts in the Thomson case are disputed, but what seems to be common ground is that Thomson - when national secretary of the Health Services Union - signed off on a credit card payment that covered the cost of prostitution services. Nobody is suggesting that Thomson himself used those services.

Essentially that remains a matter between Thomson and his union. The most that can be levelled against him now as a politician is that he once showed poor judgment.

Well, twice actually. This week, he was late updating his register of pecuniary interests, technically breaching parliamentary rules. But again that is not a hanging offence. Many MPs have done the same thing.

That update finally recorded the intervention by the NSW branch of the ALP, in that they paid part of his legal bills arising from a dispute with the Fairfax media group.

The Daily Telegraph has reported that "Labor sources" confirmed the figure was more than $90,000, with tens of thousands more in loans.

Again, that is a matter between the ALP and Thomson. If that has happened, it is unusual but not illegal.

But it is yet another indication that the Labor Party machine is ever watchful of the Thomson saga, anxious to prevent the issue going off the rails.

It might yet prove to be a white knuckle ride for Labor all the way through until the election.

But the chances are Thomson is not the main threat to the Gillard Government suffering a premature end.

Andrew Wilkie still presents as a greater threat.

As recently as August 3, Wilkie declared he would "tear up my agreement with Julia Gillard, simple as that," if legislation is not passed by May next year to introduce mandatory pre-commitment with poker machines.

The issue is muddied because the written agreement between Wilkie and Gillard stipulated that the Government "will support" legislation by the 2012 budget. But in subsequent interviews, Wilkie seems to be insisting that the legislation must pass; that if the Government's best efforts come to nothing, then the deal is off.

That sets a near impossible task for the Government. It has to go to COAG as a first step and try and win the support of the states. Zero chance of that.

Then they will need to defy the hostile states who take this issue very seriously - and proceed with rare and provocative overriding federal legislation.

But the chances are the key independents, Rob Oakeshott and Tony Windsor, won't have a bar of it either.

So the Government will then search around for compromises. But even though the industry might accept voluntary pre-commitment for example, Wilkie, aided and abetted by Senator Nick Xenophon, will not.

It's hard to see where game-breaking compromises will come from. Talk of more low-intensity machines for example, doesn't even go close to Wilkie's main concerns.

The Government can't string Wilkie along until nearer the scheduled date for the next election either. He was canny enough to set the budget 2012 as the deadline.

The only straw for the Government to cling to is that Wilkie might find it hard to transfer power to Tony Abbott, despite his threat. How would that advance his anti-poker machine cause? But then if he was to baulk at the final hurdle, he would lose all credibility. In the end, he might be guided by the mood of his electorate.

In any case, the run up to the next budget is going to be a tense time for the Gillard Government. They'll need to announce a budget surplus and a breakthrough in the poker machine issue, otherwise the whole show could collapse no matter what the state of the carbon tax debate.

Barrie Cassidy is the presenter of ABC programs Insiders and Offsiders.