So those shouting "not in my name" and "meritocracy" to argue against the possible means of all women shortlists do have a prima facie case to answer.
There may have been a fairly bland consensus among the party leaders at the Speakers' Conference. But David Cameron's claims that his party gets it enough to continue if he fell under a bus is rather challenged by the ferocity of the response from the Tory netroots to his rather modest proposal to use HQ powers in late selections to select more women. Aspiring candidate Iain Dale declares not in my name while the Isaby/Montgomerie co-premiership at ConservativeHome seems to think the sky might fall in. (Tory ppc Joanne Cash has offered a rare pro-leadership view from the centre-right).
By definition, meritocrats must share the goal of "fair chances and no unfair barriers".
The simple question: what is the cause of the scale of under-representation? And what is the solution to deliver fair chances and equal representation?
Some may think the use of the historic aggregate is an unfair dredging up of ancient history. But when we elect more men every time than we have elected women in a century, that can be challenged.
Or take a more recent, post-millennial moment: 2001 was the last General Election in which no party used an all women shortlist measure. How did we do on gender equity? Most noticed a small drop from 120 to 118 women in the Commons. The real story was missed. Just 9 out of 92 MPs elected in mainland Britain were women. Not quite 10%. (Slightly disguised by 3 of the 6 new Northern Irish MPs being women: an unlikely feminist assist). The Conservative class of 2001 - 38 white men and 1 women (2.5%)- was well below the post-1918 historic Commons average.
Whose meritocracy is it anyway?
By contrast, 26 of Labour's 40 new MPs in 2005 were women: the only party group in history to contain more women than men. 23 of them elected using all women shortlists.
Now, each of the three major parties selects women in around one in four Parliamentary selections.
This does mean that the party using all women shortlists is not now selecting more women candidates than the other two major parties which are not. Nevertheless, easily the main reason for the Conservatives and LibDems speeding up progress is that Labour went so far ahead (while still, itself, being only halfway to equity). The progress of the non-shortlist using parties is a politically necessary response to the progress made by a political rival.
This is, in large measure, a result of Labour's use of all women shortlists. The graph makes a dramatic point
See too the glacial progress before 1997:
Labour female MPs
1979: 11/269 (4.1%); 1983: 10/209 (4.8%); 1987: 21/229 (9.2%); 1992: 37/271 (13.7%) 1997: 101/419 (25%)
1979: 8/339 (2.4%); 1983: 13/397 (3.3%); 1987: 17/376 (4.5%); 1992: 20/336 (6.0%); 1997: 13/198 (6.6%)
These numbers can form the basis for a powerful case, but the shortlists debate is not an open and shut argument.
For the anti-shortlists argument to be plausible - and I don't rule that out - it needs to be based on more than polemic. It needs to be rooted in the evidence about what is happening, and to develop a serious account of why we don't have fair chances and how we might get there.
Personally, I am a moderate, cautious supporter of all women shortlists: the case that they have been necessary to deliver progress stands up, but they have limits too. Hence my concern, in my own evidence to the Speaker's Conference, that the measure can have "diminishing returns". (For much more on the data, and the complexities of the debate on pros and cons, see this earlier Next Left post on liberal means, feminism and representation).
I think that there are only three possible broad categories of reason why there might be systematically less women then men in our politics.
(i) That women are less able - and have less aptitude for politics than men;
(ii) That women are less interested in politics than men;
(iii) That there are structural and/or cultural barriers to fair chances which mean that women are systematically less likely to selected and elected as MPs than men.
(i) is simply prejudice. It may, however, be subconsciously more widely held than people realise.
Have you ever heard a vociferous critic of John Major, Norman Lamont or Gordon Brown generalise about what this reveals about the problem of having men in senior political roles? Yet those who disagree with Margaret Thatcher, Harriet Harman, Jacqui Smith or Theresa May very often tell us that this says something about women in politics. Under-representation and the novelty factor routinely legitimise this sexist response.
There are brilliant and useless MPs of both genders. Yet it seems to me fairly evident that that there are, overall, probably rather more mediocre men than women in the House of Commons right now, not least because, with five times as many men, we are digging rather further down the male ability range.
(ii) is held by some: I expect Mr Paul Dacre of the Daily Mail might think this both true, and a jolly good thing.
But, for those not relying on a traditional segregation of gender roles which would see women playing a minor role in public affairs, I would suggest that where there is evidence of a significant "lack of women coming forward" issue would speak to the need to change political culture and institutions so that they do not either discriminate against or deter half of the population.
I do not see what the foundation is for the argument that a political party should seek to offer "fair chances for those who come forward" as opposed to treating as an indicator of "fair chances" the broad balance of those actually elected or selected.
Otherwise, systematic cultural barriers which simply repelled candidates from ever applying are overlooked, and the parties' stated aspirations to reflect the society they wish to serve is lost.
There are a great many institutions in our society who sometimes say "it is not our role to try to fix society: we just select the best candidate for the job". Universities, law firms, FTSE 100 companies and newspaper editors all say this when questioned. It is both a fair point, and one which occasionally serves as an excuse for inaction too. Perhaps the last institutions which might want to say that are political parties. Indeed, progress within the political sphere could well be one way to drive a shift in the broader civic and public culture, which might affect what happens in the boardroom, the media and other areas.
(iii) is I think rather difficult to disagree with. At one level, I think that there must be some account of (iii) is universaly accepted - certainly by anyone not strongly committed to (i) or (ii). I don't think anybody denies that the gender imbalance is real and systematic. I don't think anybody has seriously suggested that it is just bad luck, and that we could just wake up after one election and find an 80% female and 20% male Parliament instead.
That does not, of course, establish a case for any particular means of addressing the imbalance. It does mean that anybody sailing under the banner of 'meritocracy' needs to have an account of how to achieve 'fair chances and no unfair barriers' for men and women.
And the two classes of MP objection is a radio talking point. I doubt it exists in the real world at all.
After all, 35 of Labour's new women MPs in 1997 were selected on all women shortlists and 30 were not. (You can find the list in the appendix of the Nuffield study, but I guarantee that you would simply be guessing if you tried to separate them by means of selection). Similarly, I simply don't see it as any reflection on the talents of incoming Labour candidates such as Rushanara Ali and Stella Creasy that one was elected by one means and the other by another. (Again, I am not telling you which!).
I am also an opponent of all minority shortlists. For those who want more than a rhetorical soundbite - either against a slippery slope (as Isaby/Montgomerie and Dale fear from the right), or in favour of applying the same methods to one issue as another (as Diane Abbott and Operation Black Vote advocate).
Dale writes: "Imposing all female shortlists is a fundamentally unconservative thing to do and one has to ask where it will lead. All black shortlists? All gay shortlists? All disabled shortlists? All christian shortlists? All muslim shortlists?"
I think that several very relevant differences apply. Some of these are philosophical and political concerns about the different consequences, as I argued in the New Statesman
The analogy is weak. Women, 51 per cent of the population, can be found almost everywhere in roughly equal numbers to men. It is easy enough to work out who is a woman and who is not. Such factors do not apply to minority representation. The call for all-minority shortlists is rooted in 1970s thinking about "ethnic minorities". This is of ever-decreasing relevance to third- and fourth-generation multi-ethnic Britain (in which mixed-race people will outnumber those of any single minority group by 2015). All-minority shortlists might not be exactly unworkable, but they would take us backwards.
But I do think that the knock-out argument is the clear evidence which I put to the Speakers' Conference.
We now know that it is possible to break down the 'ethnic penalty' to fair chances for BME candidates by current measures - because Labour has already achieved this, not much more than two decades after the first post-war black and Asian MPs were elected.
Unfortunately, nobody can make that claim on gender - where there is a longer history, and indeed a stronger base of comparative international evidence as to how often strong positive measures have been needed.
The challenge to meritocrats who think all women shortlists are the wrong route is to set out a serious argument about how to change this.
The different patterns in these different areas also raises a series of interesting questions about why the gender penalty to fair chances has proved much more stubborn than that of ethnicity: this suggests the "who can be an MP stereotype" is not as dominant a factor as is often implied, and that greater attention paid to the time and economic costs of seeking selection, and the strong effect this has on those with caring responsibilities as well as for working-class candidates of both sexes.