If you needed any convincing Labor is a party entirely adrift from its supposed values and purpose, given over now to politicking, expedience and opportunism, just wait for its reaction to Tuesday's budget.

It will vehemently oppose Joe Hockey's deficit levy - no matter how watered down it is by then - and his intention to resume indexing the petroleum excise on the basis of no stronger argument than that they're broken promises.

These are two measures Labor should strongly support if it's sticking to its principles - one that makes the tax system fairer and one that supplements the carbon tax in fighting climate change.

If Labor were truly the social democrat, progressive party it wants us to think it is, it would advocate and fight for bigger government. Bigger not for its own sake, but because there are still many much-needed services and assistance yet to be provided, with governments best placed to provide them.

As we know, Labor can always think of new ways to spend money - the National Disability Insurance Scheme and the Gonski education reforms, for instance - but when it comes to raising sufficient revenue to cover the cost of these genuinely worthy causes, Labor's courage deserts it.