John Rentoul replies that a popular policy may do longer-term damage if it implies that Labour does not like success.
I have already noted that the policy is indeed popular, across all party preferences and social groups, which I argue challenges both the class war and core vote labels.
John Rentoul's argument could be that the policy is popular but wrong. But another version of his argument could be that a policy could be popular and right - but still wrong for Labour, because it dredges up ghosts of Old Labour the party had sought to exorcise.
I am sure that those Old Labour ghosts may well form a big part of the "what would Tony do?" issue. They have also rather tempered the extent to which Labour has gone in for any banker-bashing under Gordon Brown. There has been much stronger language from Sarkozy, Merkel - and even sometimes fiercer rhetoric from George Osborne (since the Tory fear is of being associated too closely with their friends in the City).
What is being missed in this debate is that there is also an impeccably New Labour objection to the idea that the government should have no response to public anger about attempts to keep the bonus culture going with taxpayer support.
New Labour may have been relaxed about those who earned their success - but it was certainly very angry about "fat cats" who wanted "rewards for failure" and so violated its 'rights and responsibilities' arguments.
If you were to return to the little red book of New Labour, you will find that Peter Mandelson and Roger Liddle wrote in The Blair revolution ahead of the 1997 election "New Labour should use the tax system to attack unjustified privilege, without weakening incentives for risk-taking and hard work”.
Roger Liddle has written since, back in January 2008 that New Labour should express a concern about excess and unearned rewards at the top, and do so in a New Labour way.
In crude and simple terms, we need to move from a society that is afraid to ask “How much have you got?”, to one that is prepared to question “How did you get it?” This was how Winston Churchill as a radical Liberal sought to turn the political argument in defence of Lloyd George’s redistributive 1909 budget.
In the early 20th century it was landowners who were seen to enjoy gross excesses of income and wealth, for which in Neville Chamberlain’s wonderful use of Biblical language “they toil not, neither do they spin”. The gross excesses of 21st century Britain are in different social categories: directors whose compensation packages have little or no justification in terms of their contribution to the profits and success of the companies they lead; investors who take advantage of Britain’s generous capital gains tax provisions but are not genuine risk takers, building a business from scratch through their own hard work; individuals who owe their comfortable circumstances to inheritance rather than their own efforts. What is needed in the UK is a change in political culture and discourse about questions of income and wealth
A good deal of public anger at bonuses is explained by this sense that the principle of 'fair rules' has been broken. The public would appear to be making a clear distinction between the deserving and undeserving rich, as the Fabian Society's research for the Joseph Rowntree Foundation suggested.
They haven't changed their mind about James Dyson or Richard Branson - but they do more than wonder which banker could brazenly claim to have earned a mega-bonus in 2009.
So I don't think there is much evidence at all that either the 50p rate or the banker bonus tax have made Labour "unelectable". Indeed, since those constitute the two government policies which are both well known and popular, the source of Labour's political difficulties may well lie elsewhere.
PS: A further heresy would be to question whether its pledges on taxation were ever quite as central to New Labour's appeal as New Labour undoubtedly believed that they were. 71% of voters ahead of the 2001 election expected Labour to put up taxes. But that would be to challenge the New Labour worldview. My point here, in the case of bank bonuses at least, is that one need not even do that.