Scotland's decision matters to everyone Alex Salmond welcomed David Cameron to Edinburgh yesterday as though he were a visiting dignitary from some foreign land rather than the Prime Minister of this country. All quite deliberate, of course, for the Scottish First Minister's strategy for independence, while based partly on anti-English resentment, is built mainly on the notion that Scotland can stand proud in the world, unencumbered by the 305-year-old union with its bigger neighbour. Mr Salmond was beaming out the message that he has the right stuff to be a player on the world stage. Unhappily for the Scottish National Party leader, the voters are not with him. Opinion polls have for years suggested a broadly two-to-one majority against outright independence. Indeed, almost half the people who voted SNP at the last election say they are opposed to going it alone. Now Mr Salmond's bluff has been called by Mr Cameron, who has negotiated astutely, and he has two years to mobilise a majority in favour of separation. That may seem a tall order, but this wily operator is certain to produce a lively box of political tricks during a campaign that has finally opened in earnest with the signing of the referendum agreement. That makes it imperative that the pro-Union campaign concentrates on making a positive case for the status quo, rather than simply deploying the fear argument. It is true that an independent Scotland may struggle to find its feet economically - Iain Duncan Smith warned recently that it would not be able to pay its welfare bills without tax rises and spending cuts elsewhere. And Mr Salmond's claim that it would maintain not only its membership of the EU but also the UK currency and the Queen as head of state looks rather fanciful. However, the debate needs to rise above negative lines of attack. There are bigger themes to be explored - the fact that this union has been the most successful such link-up in history; that we are stronger working together than we could ever be apart; that as a Union we have regularly punched above our weight in the world; that separation would have profound consequences not only for the way the rest of the United Kingdom is governed and defended, but for the texture and direction of the international community. It augurs well that when Alistair Darling, the respected former Labour chancellor, launched the "Better Together" campaign earlier this year, he emphasised the advantages of maintaining the Union and argued that "loving Scotland does not mean leaving the United Kingdom behind." That struck exactly the right note. It is the responsible and mature way to confront the most profound constitutional challenge our United Kingdom has faced in centuries.