The fact is that the Brexit camp is fighting an dreadful campaign.
The fish rots from the head, and leadership is the first problem that the Brexiteers face. Farage and Johnson posture, but do not lead. Meanwhile Michael Gove has made his case and quietly returned to government. Only IDS continues his angry way, irritating his Conservative colleagues, but not really landing a blow.
In the engine room, controversial but not competent figures such as Arron Banks or Dominic Cummings have a set a hostile and provocative tone which has even alienated their own supporters.
The campaign is divided- unable to put forward a clear vision of a post-EU future, because they can not agree on whether that should be completely separate, an association agreement, or full membership of the EEA. Meanwhile, despite the large amounts of cash available, the campaign is disorganised and increasingly dispirited. The polls are running increasingly against the Leave campaign.
A badly led, divided and weak Leave campaign was always going to struggle, but the unappealing personalities at the top seem to be condemning them to defeat, and possibly even a rout.
Of course nothing is certain, but from the point of view of the Conservatives, an unexpectedly wide margin of victory would open up several questions. Firstly the impact of a decisive victory on British politics could be interesting. Cameron has bet the farm on winning- and he has certainly proven extremely effective at destroying his enemies.
The Lib Dems underestimated him, and not only did he put his tanks on their lawn, he pillaged their camp and scattered salt in their fields. In Scotland he has helped the SNP to rout Labour, and as the SNP tide turns, there is a real prospect that the Scottish Tories under Ruth Davidson (as Cameroon figure as there is in Scotland) could snatch a share of government in 2021, and many MPs in 2020. Labour is in disarray, and the chances of a recovery on either side of the border, for as long as Corbyn is in charge, seem ever more remote.
So the biggest threat to the Prime Minister is the heidbangers on his own side. The bitterness amongst the Tory Leavers is palpable and in fact they may decline to function to the Tory whip in the coming months: the government only has a majority of 12, and there are many times that number who will be completely hostile to the Cameron-Osborne camp regardless.
Then there is the cloud no bigger than a mans hand- the expenses scandal. IF that were to break, then the Conservatives would really be in trouble.
So even as Cameron seems set to complete another victory, having exorcised Scottish separatism and UKIP rejectionism, he still faces further battles. Although he is already quite a long serving PM, it may take another election before he can claim to have actually changed his party and his country, and the electoral commission or his own MPs may still deny him that chance- assuming that he even wants it.