I'll say a couple of words.
All the new members of NATO have become members through a referendum. That's the reason that in Finland we have to look carefully at what the people think about this. Almost all the eastern and central European countries had a referendum on NATO. Now, according to the Finnish constitution, it's not obligatory to have a referendum. But like EU membership, the possibility of NATO membership could be an issue for a referendum.
About this constitutional role of the Parliament and the foreign affairs committee, in Finland almost all the international treaties have to be accepted by the Parliament. That's the reason the government has to listen to the views of the Parliament. Only when the treaty has nothing to do with legislation or budgetary questions and issues is it possible to ratify it by the government and the president only. But I think 95% of the international treaties are accepted by the Parliament