Scottish independence: Alex Salmond 'certain' on Nato membership
First Minister Alex Salmond said he was "certain" that Nato countries would accept an independent Scotland opposed to nuclear weapons into the alliance.
Nato has said that if Scotland was considered to be a "new state" it would need to reapply for membership.
Mr Salmond said membership could be negotiated in the period between a "yes" vote in the referendum and Scotland actually becoming independent.
The SNP voted last year to change its position on Nato.
Nato is a military and defence alliance of 28 member states across North America and Europe.
Mr Salmond, who is currently in the US for the Scotland Week celebrations, told the Brookings Institution in Washington DC on Tuesday that an independent Scotland would become an active member of organisations such as Nato, but insisted nuclear weapons systems such as Trident would be removed from Scotland.
Speaking to BBC Scotland after delivering his lecture, Mr Salmond said: "You have to come to agreement with your colleagues, and in that sense there is a parallel with the European Union - you notify your intent to remain a member.
"We are a member by virtue of our membership of the United Kingdom, and we notify in that period between the referendum, and a successful vote, and the adoption of Scottish independence about 18 months later".
Nato said it had had no discussions on the possibility of Scottish independence, and pointed out that any arrangement would have to be agreed by all member countries.
But it said that a new state would not be a party to the North Atlantic Treaty, and therefore not a member of the alliance, while the position of the "successor state" would be unaffected.
In a written response given to BBC Scotland, it said: "It appears widely agreed that, as a matter of law, a Scotland which has declared its independence and thereby established its separate statehood would be viewed as a new state.
"In the Nato context, the definitive determination on this question would be made by the member states, acting in the North Atlantic Council.
"A new state would not be a party to the North Atlantic Treaty, and thus not a member of Nato. If it were to choose to apply for Nato membership, its application would be subject to the normal procedure, as outlined in Article 10 of the Treaty."
Labour peer Lord Robertson of Port Ellen, a former Secretary General of Nato, said membership created a "huge dilemma" for the SNP.
He said any state applying for Nato membership had to accept it was a "nuclear alliance".
"Does the SNP accept this unambiguous acceptance of the nuclear umbrella?," he said.
"I supervised the entry of seven new members to Nato in 2002 and every one of them had to accept the Strategic Concept. If the SNP cannot accept the Nato Strategic Concept then it will simply not get in.
Scottish Conservative leader Ruth Davidson said: "The SNP's chaotic approach to Nato, and the wider issue of defence, is simply to stick its fingers in its ears and hope the assertions repeatedly made will eventually come true."
The SNP is committed to non-nuclear membership of Nato, and the rapid removal of Britain's nuclear weapons from Scotland.
Mr Salmond, who has met with former US Secretary of State Colin Powell during his visit, said he did not believe his party's stance on nuclear weapons would be a problem when it came to Scotland's membership of the military alliance, and pointed out that 25 of the 28 members of Nato were non-nuclear.
He said: "It is the exception rather than the rule to be a nuclear country - only Britain, France and America possess nuclear weapons.
"Many members of Nato, like Canada and Norway, have made it clear they won't host nuclear weapons on their soil, and that is respected by the other partners in the alliance.
"They are still fully signed up members of the Nato alliance, so Scotland's position is not different from other countries, nor is it an unreasonable one, and I am certain we would be accepted by the other countries.
"From everything I hear, there would be enthusiasm for that continuing membership. I don't expect this to be difficult negotiation at all, I think it would be more of a difficulty for our friends and allies if we were going to adopt a different defence posture."
Kurt Volker, the former US ambassador to Nato, said there was likely to be "great goodwill" from Nato members towards an independent Scotland's application for membership of the alliance.
He added: "To the extent that Scotland says 'we are now independent in security and defence' then it is out and it has to reapply to become a member of Nato, because one would assume the successor state would be the United Kingdom and Scotland would be seen as any other country that would seek to join Nato.
"Obviously, there would be great goodwill towards Scotland as it has already been a part of the alliance for so long and there is no reason to have any concern or objections to Scotland being a member, except if it is changing the terms of its membership as it would relate to the interests of other members, and that is what we would need to then look at more carefully."
Mr Volker, who now runs the McCain Institute on behalf of the former presidential candidate John McCain, said Scotland may not have to reapply for membership if, for example, it chose to share its defence with the rest of the UK, in the same way as Mr Salmond wishes to share a currency.
He said: "If the mechanics are such that Scotland is part of a UK defence decision-making structure, and it is covered by that, then there is presumably a way it could be negotiated with Nato to remain a part of Nato, before the point of independence or as independence is realised, because the question on a referendum is, as I understand it, very broad.
"There is a lot of lawyering that will go into how all that happens, and it could be done in such a way where the defence relationships would not be changed, and therefore perhaps not changed internationally."