Somewhere in a rubbish skip outside Parliament House there are two boxes marked 'credibility' - one from the Government and one from the Opposition.

Somewhere in the last couple of months the Government must have decided it was taking up too much room in the office and chucked it.

And watching as it happened, the Opposition must have decided it too needed a spring clean.

There doesn't appear to be another explanation for what has been happening in Federal politics.

The Government started the trend with a pre-election clean out of problems. It scrapped the insulation program and junked the election promise to build childcare centres.

Then, courtesy of the Prime Minister, the box of credibility went out too, as he put the emissions trading scheme in the deep freeze.

It was a move that brought Mr Rudd's past back to haunt him with a recitation of the times when he'd equated delaying action on climate change with denial and political cowardice.

The reason given for delaying the scheme beyond 2012 was that it wouldn't be clear until at least then what the rest of the world was doing. This is despite the Government having built the Australian scheme around a 5 per cent cut in emissions not conditional on any other country signing up, and had factored in other countries not acting by compensating Australian industries that would have to compete with those in countries that had no ETS.

It was unsurprising when the opinion poll ratings for the Government and Mr Rudd began to head south.

Then there was the response to the Henry Review where the Government took up a tiny number of recommendations but in backing the Resources Super Profits Tax bought a fight with people who have deep pockets. The Government will need all its skills in salesmanship, which have not hitherto been on display, to win this one.

The budget disappeared, as budgets do these days, without leaving a forwarding number.

Now poll after poll shows the Government is in danger of losing the election, and Kevin Rudd has lost his gloss.

So what is an Opposition to do? Polls going well, Government on the back foot - perfect time to toss out it's own credibility apparently and in some very odd ways.

Tony Abbott admitted that, "in the heat of discussion", his words may not exactly be the "gospel truth", which is something only guaranteed when his thoughts are pre-prepared (by the act of writing them down). as a speech or policy document.

Somewhat oddly, he was commended by some for his refreshing honesty about saying things that weren't completely true (That interview on The 7.30 Report followed one on the same program by Kevin Rudd where some Labor MPs were relieved to see the Prime Minister showing a bit of passion on the ETS... although it was pointed out to them that he was being passionate about abandoning a principle).

The Opposition has also chosen the last week to run a course in "What not to do" when you're making a major economic statement.

And it managed to invent what came dangerously close to looking like an actual game of political football as Tony Abbott passed the task of detailing Coalition spending measures to Joe Hockey who then passed it to Andrew Robb.

Mr Abbott had, in a written down speech told the Parliament Mr Hockey would detail the savings at his Press Club address.

Mr Hockey didn't. And the list of savings wasn't available for the reporters to ask Mr Hockey about.

Mr Hockey says he didn't want his speech on the Coaltion's economic principles to be overshadowed by the details of the spending cuts, and told the audience Andrew Robb would talk about the list.

But in doing that, the story was not only not about Mr Hockey's principles nor about the details of the spending cuts, but the breaking of the promise Mr Abbott had made in Parliament and the failure to allow scrutiny of the proposals during Mr Hockey's press club event.

Mr Robb copped the full force of journalistic dissatisfaction 45 minutes later, not helped by some hard questioning of the spending cut decisions especially on the inclusion of savings created by not proceeding with a mining tax that hasn't started yet.

As a process designed to restore the Coalition's economic credibility, the Budget Reply Reply Reply (the Abbott version, the Hockey version and the Robb version) was not a wildly successful affair.

It did seem though to be proof that in politics shooting yourself in the foot is actually a virus that can be passed from party to party.

And as autumn meanders towards winter, there in the skip outside Parliament, the two boxes of credibility lie. And as anyone who's tried to fish anything out of a skip knows, the throwing away is the easy party. Getting it back is much harder.