Truth is the first casualty in war, but the same applies to politics. This has been graphically illustrated during the British election campaign, as all sides try to close down post-election options for others while keeping their own preferred choices in play.
On Thursday, Nicola Sturgeon was applauded by a London audience during a BBC-hosted TV debate when she criticised Labour Party leader Ed Miliband for refusing to commit to a pact with her Scottish National Party.
"We have a chance to kick David Cameron out of Downing Street. Don't turn your back on that. People will never forgive you," Sturgeon said emotively, adding that she wanted "Ed to replace the Tories with something better".
The demand by the Scottish First Minister that Miliband signs up now for a post-election voting pact is nonsense. Sturgeon, who is seeking to destroy Labour in Scotland, knows it. Everyone involved in the campaigns knows it.
So too does the British press covering those same campaigns, yet it is still reported as if it is an entirely serious proposition. The London Times could report it under the headline, "Join Me, or You'll Pay, Sturgeon tells Labour".
Adding it up
The reason why it is nonsense is simple. Post-election options will be decided by numbers, nothing else. If Scotland was still the source of 40-odd seats for Labour, as it has been so often in the past, for so little effort, Miliband would already be measuring the curtains for No 10.
But it is not. Indeed, the question is whether Scotland will produce any Labour MPs at all, if the most extraordinary of the opinion polls reflecting the rise of the nationalists have accurately gauged the winds.
A Labour minority government that comes home with a couple of dozen Scottish seats is an entirely different beast to a Labour minority government that is left denuded of credibility by having little or no representation in one part of the UK.
Therefore, Miliband must argue for a Labour majority and for the maximum support that can still be winkled out of Scotland in order to hold on to distant hopes of governing on his own.
Or, far more likely, to ensure he has a negotiating hand to play against the SNP, or is open to any other permutation that could get him over the line.
The fact that hopes of Scottish support are evaporating, not increasing – as illustrated by the latest batch of polling from Lord Ashcroft – does not mean that Miliband is wrong to be acting as he is.
Common cause
Nevertheless, politics is often a fact-free zone. Speaking to reporters downstairs later in Central Hall in Westminster, leading SNP figures earnestly emphasised their desire to find “common cause” with Labour to keep the Conservatives out of power.
So far, however, the Conservatives’ bid to paint Sturgeon as a destructive dominatrix has failed. English voters have seen her in several debates: at best, they have been impressed; at worst, they do not regard her as a marauder.
Indeed, an Evening Standard poll last night of 1,000 people across Britain (not including Northern Ireland) found that just 24 per cent say the SNP is the party they least want to have influence after May 7th. In contrast, 42 per cent do not want Ukip anywhere near the levers of power.
Sturgeon's "the people will never forgive you" demands for a pre-election declaration by Miliband excited the debate audience – one that was criticised, with some justification, by Ukip leader Nigel Farage for being too left-wing.
With his refusal to sign up to her demands, Sturgeon can paint Miliband as a weak leader to Scottish voters who might still need persuasion to drop old loyalties to Labour, or whose determination to vote SNP may wobble in the final weeks of the campaign.
Equally, she knows that the idea of such a pact infuriates Conservative-leaning newspapers, who can be expected to continue fulminating in culturally insensitive ways about the undue influence to be enjoyed by the Scots.
Coalition talk
Even more successfully from Sturgeon’s point of view, her call for a pact led to repeated headlines on the BBC about Miliband “ruling out coalition” with the SNP, even though Sturgeon has never offered such an alliance.
Apart from anything else, much of the British debate about Sturgeon’s cleverly organised tactics misunderstands – often deliberately – the nature of the parliamentary arithmetic that will come into play after the votes are counted.
If granted permission by Queen Elizabeth to form a government, Miliband will seek the approval of the Commons. He will then produce a Queen's Speech – his legislative plans. Later, Labour will have to produce a budget.
It is Miliband who will be asking Sturgeon – or a mix of Liberal Democrats, Plaid Cymru and others, should a deal be possible in that direction – to join him, not the other way round.
However, confident declarations of some that a minority government is inevitably destined for a short life and that it could not possibly succeed display a poor understanding of the effects of the Fixed-Term Parliaments Bill.
The 2010 legislation, forced through at the demand of the Liberal Democrats, means that a minority government could survive a defeat on its Queen’s Speech.
It could, incredibly, even survive a defeat on a budget vote. Such a government, properly managed, could run for years.