Limiting the amount anyone could contribute out of their own money into tax-advantaged super on top of employer contributions was never retrospective, but those who thought it was can relax. The government is imposing a limit by another means.

The plan was to impose a lifetime limit of $500,000 - a figure so large as to be of use to less than 1 per cent of the population. How many of us know someone who can afford to pay money into super over and above their employer contribution and has half a million to spare?

It was said to be retrospective by many on the Prime Minister's own side because high earners might have planned for something else. Which makes it about as retrospective as a tax cut, or a price rise: it applies to future actions, but someone might have planned for something else.

The replacement regime will be just as (non) retrospective, but it'll be harder to paint as retrospective. Anyone who wants to put extra into super from their own funds will be able to do it up to $100,000 per year, down from $180,000 per year. Because only the size of the limit has been changed rather than its form, it'll be harder to claim that the nature of it has changed.