"Soft compulsion" is the jargon for the proposal attributed to Lord Turner for signing up all employees who do not actually object to contribute to a new national pension fund.
Employers would be signed up, too, without any opt-out for the unwilling. The money would be collected along with PAYE and National Insurance.
The best thing about this notion is that a national fund will become so vast that the charges should be low enough to give a worthwhile fillip to the investment performance.
The second best is that it is better than hard compulsion with no opt-out - but not that much better. It needs a rare, watchful bloody-mindedness to scratch out one line on a catch-all form the day you arrive to start a new job.
You can bet your boots there won't be independent advice on hand. And if opting out somehow does become fashionable, the project will be a flop. The whole idea is that almost everyone will join out of inertia.
The objections to "hard compulsion" all remain. Christine Farnish, chief executive of the National Association of Pension Funds, voiced some of them yesterday. Low-paid people in particular could be no better off at the end of it.
They may get nothing when they retire for the money they are bamboozled into paying. It will depend on what they lose in means-tested benefits --which will depend in turn on what means-testing rules are in place however many decades into the future.
Nor can anybody honestly suggest what sort of a pension any level of contribution should buy. You can work out the size of a "pension pot" that so many pounds a month should produce with an investment return of such and such per cent. But the likely buying power of the pension that pot secures will depend on interest rates when the time comes and how long everybody else is living. Again, un-guessable.
It is not certain either that compulsion of any sort will close the much-touted " savings gap". People who are inclined to save anyway may find they cannot afford compulsory as well. Some will end up saving no more than before - with the handicap that their nest-egg is quarantined in a pension fund.
Nobody goes through life without some sort of financial crisis. But one of the tax rules for pensions is that you can never dip into your fund in an emergency. You cannot even offer it to the bank as security. That may be very wise and proper, but it makes pension savings less flexible - so less valuable - than other savings.
All that is without into the difference between almost compulsory contributions and a tax. Few employers will detect any. Then what becomes of National Insurance?
With a little ill-luck Gordon Brown or his successor will say, "Of course it was always a tax, I'll lump it in with income tax."
That would go down badly with pensioners.
One of the more attractive privileges of old age is that you don't pay NI on your income from whatever source. Stop that and the outcry over council tax will seem like mellow birdsong in comparison.