Nato membership would be a “cornerstone” of an independent Scotland’s security policy, Nicola Sturgeon has said. The First Minister reaffirmed her party’s commitment to joining the alliance if Scotland leaves the UK on the same day Scottish Greens co-leader – and Scottish Government minister – Patrick Harvie said his party was opposed to membership. Speaking at the Brookings Institution think tank in Washington DC on Monday as part of a foreign outreach trip, Ms Sturgeon said: “The party I lead, the Scottish National Party determined back in 2012 – at that time a reversal of a longstanding position – that should Scotland become independent it should seek membership of Nato. “There is no doubt that the events of the last three months have strengthened my conviction that this position is absolutely the right and essential one.