Contrary to popular opinion, politicians rarely lie. By the time they've said an explicit untruth, they have primed a bomb which could go off at any time in their future career. This is not to say politicians are truthful. They are not. They are among the least truthful people in the world, together with management consultants and prostitutes. But they do not lie. They evade. Looking for the lie is generally a waste of time, looking for the evasion is far more profitable.
With that in mind, let us consider an undisputed fact about David Cameron. The prime minister has been asked whether he discussed plain cigarette packs with election guru and tobacco lobbyist Lynton Crosby at least 12 times, and each time he has replied using what appears to be a form of evasion. Each time he is asked if he had a 'conversation' with him, he answers that he was not 'lobbied' by him.
"Lynton Crosby has never lobbied me on anything," he told Labour MP Kevin Barron in the Commons.
"I have answered the question: he has never lobbied me on anything," he told Ed Miliband.
"As I said I've never been lobbied by Lynton Crosby about anything," he told the BBC's Nick Robinson.
"You said you weren't lobbied by Lynton Crosby but can you answer this word, did you discuss tobacco packaging, the word 'discuss'," ITN's Lucy Manning asked him.
"Look, I've been very clear about this," he replied. "Lynton Crosby is employed by the Conservative party to advise us on political strategy and dealing with Labour and the rest of it. He does not advise on government policies and he has not lobbied me on any government policies – I've been very clear about that."
And on, and on. No matter how many times you use the word discussion, Cameron will reply with lobbying. It's clear evasion. Labour can smell blood. Everyone can smell blood. But there is, as the prime minister is well aware, no evidence linking Crosby, the prime minister and the coalition's U-turn on plain packs.
Miliband has reported the matter to the Cabinet secretary, although that's unlikely to go anywhere.
Downing Street's reaction is to publish a lobbying bill which pleased precisely no-one. It would not, of course, have affected Crosby, although there were reports later in the week that the Australian bruiser might be planning to drop his lobbying operations in time for the new year anyway.
Cameron typically responds to questions about Crosby with a reference to Miliband's union links. That tactic has played well so far, but it will become much less effective once the Labour leader is seen fighting a reforming battle over his own party's funding. Cameron has managed to get away with this evasion so far, but he'll be pleased the summer recess is here.
For all the troubles he brings, Crosby's presence has been a bit of a lifesaver for Tory morale. Rebellious Conservative backbenchers are showing more discipline, not least because of his efforts to reach out to them with more upbeat polling details. There is a sense among Tories, for the first time in a long time, that they could win the next election, or at least return to a coalition with the Lib Dems.
The stamp of Crosbian electioneering can be seen throughout the Tory party, like a stick of Brighton rock. The two key attributes are a solidly right-wing message on emotive issues like welfare, crime and immigration and resolute party discipline. The flip side is that government U-turns on plain packs, minimum alcohol pricing, fracking and gambling all seem to bear his mark too. You take the rough with the smooth.
The Tories' newfound confidence was expressed most convincingly in Jeremy Hunt's efforts to tarnish Labour's reputation on the NHS. It was only partially successful, but partial success is considered highly impressive in this policy area for the Conservatives. There was a flip side here too. The health secretary was subject to considerable criticism by the medical community for politicising hospital deaths. It was pretty dirty stuff, but the image of a Tory going on the attack on a subject like the NHS will have helped convince Conservative MPs they could conceivably get back their sense of momentum in time for 2015.
Is any of this newfound confidence justified? Don't look to the polls for advice. This month's Guardian ICM survey actually put the Tories and Labour neck-and-neck, but it could be (and probably is) an outlier. Most other polls have Labour between seven and 11 points ahead. Nevertheless, the details continue to make depressing reading for Miliband, whose personal polling is consistently disastrous.
That's one of the only consistent elements of current polls, actually. Apart from that one element, they are all over the place. Ukip are either consolidating their spring local election surge or sinking into the sand, depending on who you read. Their polling is particularly chaotic.
But an Ashcroft survey did give a clear indication of one thing: the public aren't keen on the 'alternative Queen's Speech' assembled by a cabal of troublemaking Tory MPs. People aren't really up for privatising the BBC, establishing a Margaret Thatcher day or banning the burka, funnily enough Turns out voters typically want their politicians to be to the left of Attila the Hun.