In a July 2019 letter to parliament, the Dutch Minister of Foreign Affairs set out the Government’s views on “the application in cyberspace of relevant elements of existing international law.” That letter has now been made public. It is an extremely granular statement, not only in terms of scope, but also with respect to the legal basis for the positions taken. As such, it is a major contribution to the growing body of opinio juris on the subject that includes the recently released French Ministry of Armies’ International Law Applicable to Operations in Cyberspace, (see here, here, and here), the Estonian President’s speech this year, the UK Attorney General’s Chatham House speech last year, and Australia’s current International Cyber Engagement Strategy (annex on international law).
International cyber law is a subject close to home for the Netherlands, which in April 2018 was the site of a Russian military intelligence (GRU) cyber operation targeting the Organisation for the Prohibition of Chemical Weapons. The country clearly understands that clarity in international law can serve deterrent purposes , lessen the likelihood of unintended escalation in cyberspace, and enable certain robust responses to hostile cyber operations (see netherlands releases force international cyberspace
