Brexit4. Cameron's campaign

For a man that was once considered a eurosceptic it has not gone unnoticed how hard David Cameron has been prosecuting the 'Remain' case. Indeed, in his endeavour to win at all costs he has formed alliances with former enemies including those he had accused in the House of Commons of colluding with groups harmful to the security of the Nation.  He has corralled the Civil Service, all the financial agencies, businesses, trade unions etc sympathetic to the 'Remain' argument, ignoring any opposition or negative comments even from those people he called his friends.
This fervour has led me to question why, when surely there is only one issue: should the UK recover its undiluted sovereignty or stay in the EU. Put in these simplistic terms, Cameron, shouldn't need to push for the win- at- all- costs strategy, scaring the voters with threats of Armageddon, plagues, financial meltdown etc. So what is it that has got the PM so worked up? It's almost as if Cameron has been given an ultimatum; win the referendum or die.
Well, maybe not that harsh but something like that. He negotiated with the EU elite and got nowhere, coming back with meaningless promises but was there something else. I don't suppose that the EU constitution has a 'treachery' clause like almost every single nation has, usually backed up with the death penalty, but what else might the smarmy bastards have lined up for him. Should the UK vote to leave have they threatened us with 'Judas' status, accusing us of being a Nation of betrayers. Have they spelt out the penalties for leaving the EU? It's not easy to see how they can harm the UK in the event of a 'leave' win but might they appeal to the US and China to have the UK kicked out of the Security Council or the G7. Will they try and marginalise our influence in the world, perhaps rewrite history? I wouldn't put it past them but maybe it's simpler than that. Maybe they have some intelligence on Cameron himself-or his family but whatever the reason, he surely can't believe that when its all over, everything will return to normal. His campaigning modus operandi has put paid to that.