The case against Lynton Crosby is that his cost is higher than his price – not only to the Conservatives, but to British politics as a whole.  Modern campaigning is focused on a minority of voters in a minority of seats.  The case for the prosecution has it that Crosby exemplifies the decision by all the main parties to concentrate on these, and let the millions of other electors go hang.  Younger people, public sector workers, members of ethnic minorities, city-dwellers (especially northern ones), the inhabitants of safe seats held by other parties, even those who live in marginals that aren’t target seats – all these, the voters that the Party needs to win big, are ignored.

Furthermore, the means to his end are wrong in themselves, and there’s no sign that the end will be achieved in any event.  Essential long-term work on those groups of voters not deemed essential is left to rot, as money and resources are pumped in to target seats: the 40/40.  Candidates who give up their careers to fight constituencies – sometimes even marginal ones – are told not to offer their brains, energy and time to the communities they want to serve, but to take themselves off to the nearest target seat, together with the money they’ve raised.  Donors are approached behind candidates’ backs and are told to stop funding them and to give to a 40/40 seat instead.  Commons seats are treated “as baubles to be handed out as a form of patronage”, in the words of a senior Government special adviser.  Ministers are told that the basis for promotion is not whether they’re good at their jobs, but how hard they work on party business.  MPs are treated as canvassing fodder.  As for other party members, they might as well not exist at all, for all the notice that is taken of them.

And still all this has not produced a clear opinion poll lead.

The case for Crosby is that it is unjust to load the sins of contemporary campaigning on one man’s shoulders, that any blame lies with the men who have hired him – and that, in any event, he is a thousand times more effective than what came before.  When he took over, it runs, there were so many barnacles on the boat that it was sinking under their weight – gay marriage, “green crap”, the pledge to throw the whole Government’s weight behind putting the 0.7 per cent aid target into law, wavering over immigration and EU policy.  Almost single-handed, he has scraped them off – producing the simple, straightforward conservatism for Bolton West which this site and others were yearning for.

Besides, the charges against him are unfair. Labour and UKIP campaign professionals are also focused on their core votes and target seats, to be delivered respectively through banging on about the NHS and immigration – but no-one singles them out as svengalis.  And when Ministers were told that promotion would not hinge on the quality of their work, Crosby stood at the side of the Prime Minister, the Party Chairman and the Chief Whip: confirmation that the 40/40 strategy is a collective endeavor, not the campaign chief’s personal brainchild.  Accusations of the fixing of selections are rubbish – as the result of the most recent one in a “safe” seat proves.  (Victoria Borwick is scarcely some stranger to Kensington, imposed on helpless Association members by an overweening high command.)  In any event, the quality of the next generation of Conservative MPs is high, according to a study of it by this website.  Finally – and most importantly – the whinges and gripes are beside the main point, which is: the party isn’t a debating society. It exists to win elections. Crosby is a winner.  Nobody does it better.

And certainly, the trend of the polls is favouring the Tories, just as he told them it would.

What is your verdict, ladies and gentlemen of the ConservativeHome jury?  The merits of the case are weighed in this morning’s Guardian by Andy Beckett – further evidence of the fascination with which Crosby is viewed by his political opponents.  You will offer your own judgement.  Mine is that the trial is misconceived.

This is because the most profound question for the Conservative Party isn’t whether or not the Boringsville approach to politics, as Tim Montgomerie has called it, is a good or bad thing in itself.  It is, rather: how big does the Party want to think?  What percentage of the vote is it aiming to win, longer-term?  How wide is its vision?

If you want a cold, clear, calculating campaign aimed at winning about 35 per cent of the vote, whose main feature is the drawing of dividing lines that puts the opposition on the wrong side of them, and whose theme is security, then Crosby is your man – though, as I say, the whole collective Tory leadership is responsible for the current election push, which is why this site refers to Ozbyisation.

But as “a former senior Tory MP” tells Beckett, “there’s not much warmth in this [election] campaign”.  Ozby doesn’t do warmth – that’s to say, Clintonesque or Reaganesque uplift and inclusivity: a sense that everyone is welcome aboard that boat from which those barnacles have been so meticulously scraped – younger voters and UKIP defectors alike.

You may say that such an appeal would be incoherent, and that a campaign which tried to make it would collapse beneath the weight of its own contradictions.  But Boris Johnson seems to be able to manage the trick.  He has won twice in London – naturally a Labour city.  The foundation of those victories was his unique appeal, not his campaign manager’s techniques (useful though they were).

Cameron is very far from being home and dry in this election.  A majority is on the edge of possibility. Leading the largest party is more likely.  If he returns to Downing Street, he will have to work out how large his Party’s ambitions should be for 2020.  It will have to make a broader appeal if his aim then is to win big.