With the exception of Paddy Ashdown, astonishingly few politicians and commentators have made the link between Scotland and Europe. But Cameron's decision to isolate the UK has significant implications for the Scottish National Party [SNP], which has long campaigned for "independence in Europe ". As Ashdown wrote  in the Observer, "If England is to be out of Europe, why should Scotland not be in?"
From one perspective, Cameron's stance strengthens Alex Salmond's argument that Scotland needs independence to pursue its own policy of European integration. As the SNP leader wrote in his letter  to the PM:
Last week's developments in Brussels demonstrate that Scotland urgently needs a voice at the top table when our vital national interests are being discussed, by becoming an independent member state, instead of being shut out of the room.
He followed that up with "six crucial questions" for Cameron on Europe and Scottish interests. But if you strip away the rhetoric, Salmond is avoiding some inconvenient questions of his own.
Until recently, the SNP leader proudly declared that an independent Scotland would join the euro. In 2009 , he quipped that sterling was "sinking like a stone" and argued that euro membership was becoming increasingly attractive. "There is no doubt that the plummeting pound and parlous state of the UK economy has caused many people in the business community and elsewhere to view membership favourably," he said. That, to put it mildly, is no longer the case and, consequently, Salmond has changed tact. Like Gordon Brown circa 2003, he now states that Scotland will retain the pound until it is in the country's "economic advantage" to join the euro.
Whether or not that day comes, there is no majority for Salmond's stance. Polling shows that the Scottish electorate is only marginally less eurosceptic than the UK electorate as a whole. According to a recent YouGov poll , 44 per cent of Scottish voters want to leave the EU (38 per cent want to remain) compared to 47 per cent of UK voters. Similarly, 45 per cent of UK voters think that Britain's EU membership is a "bad thing"  and so do 41 per cent of Scots.
Even if Scotland were to join the euro, would Salmond sign up to a fiscal union? Having finally won autonomy over spending and borrowing would he happily submit his annual budgets to Brussels for approval? How would he respond if the EU blocked his long-promised cut in corporation tax? Until he answers these and other questions, Salmond has little right to lecture others.