So I asked him, after his Hugo Young lecture, if he would do what David Cameron could not do in his own speech last year - and explain why social mobility slumped in the 1980s. I also wondered whether the LibDem leader could identify any lessons for Britain from why social mobility is highest in Sweden and lowest in the United States.
His reply is included in my blogpost at Left Foot Forward on Nick Clegg and the social mobility mystery.
”The evidence on social mobility is extraordinarily difficult to unpick”, he said. Some of the data is from the 1970s. It was not always clear what was going on. He extended that point to note too that “the comparative data is very complex”.
But he went on to make one substantive point that went beyond the general point that the international evidence was complicated.
“One thing is that a society where the gap between top and bottom is narrower, in a sense, it is easier to measure social mobility, because there is less distance to travel“, he said.
He then returned to the UK, and said he thought that a particularly significant and “distinctive” feature in the UK was “the extent of social segregation in the education system”. He talked generally about how he felt that this was important, saying he felt this was reflected in the PISA studies and the research of the Sutton Trust, and how he was confident that the Coalition was seeking to do something about this.
That was about all.
Michael White cites (anonymous) irritated Labour bloggers - "How can a Lib Dem leader, even one in coalition with the Tories, suggest that increased social mobility is an alternative to greater equality of income in the drive for fairness and social justice, they asked each other? Both are essential. Doesn't he read the books?" - before agreeing that the central weakness in Clegg's argument was in "replicating the sleight of hand David Cameron deployed when he delivered a weightier Hugo Young lecture in 2009".
Clegg's response now leaves us 0 for 2 in our ongoing attempts to get senior Coalition figures to explain the causes and consequences of perhaps the biggest social shift in modern Britain. The Institute of Fiscal Studies has noted that "the scale of this rise in inequality has been shown ... to be unparalleled both historically and compared with changes taking place at the same time in most other developed countries”, to quote the quote deployed by Richard Reeves, now Nick Clegg's Downing Street advisor, in setting out why he, Reeves, found the Cameron evasion "dishonest" a year ago.
We'll keep trying. It is surely going to be very difficult to have an effective strategy to restart social mobility without rooting that in a coherent account of its collapse.
And surely a Coalition LibDem should find it easier to say something about the social consequences of the 1980s than the Tory PM?
So let us now extend a pluralist hand in seeking to engage with this mystery of the missing social mobility in Britain.
Next Left now invites "progressive Conservatives", Liberal Democrats, whether "old progressive" or ""new", inside government or outside it, to engage with the challenge created by Nick Clegg's lecture - by offering their own explanations of Britain's social mobility slump, including any views about whether it was related to the stark rise in social inequality in Britain or not.