Hungary’s parliament voted to ratify Sweden’s membership bid to the North Atlantic Treaty Organization (NATO) on Monday, officially becoming the final NATO nation to approve of Sweden’s accession. As a result, Sweden is poised to become the thiry-second NATO member state upon formal invitation of NATO Secretary-General Jens Stoltenberg.

Article 10 of the NATO Treaty requires a “unanimous agreement” of all member states to “invite any other European State in a position to further the principles of [NATO] and to contribute to the security of the North Atlantic area to accede to [NATO].” By a vote of 188-6, Hungary’s parliament demonstrated an overwhelming approval of Sweden’s bid. During a press conference earlier this month, both Secretary-General Stoltenberg and US National Security Advisor Jake Sullivan expressed optimism over Hungary’s ratification.

Sweden applied for accession to NATO alongside Finland in May 2022 in response to Russia’s invasion of Ukraine. Finland shares a border with Russia, and while Sweden does not, it is geographically very near. While most member states swiftly ratified Sweden’s bid, Hungary and Türkiye initially opposed Sweden’s accession. Türkiye President Recep Tayyip Erdoğan notably expressed his dissent to Sweden’s membership bid due to public burnings of the Quran. Ultimately, the Turkish National Assembly approved Sweden’s accession in January 2024.

In response to Hungary’s vote of approval, Secretary-General Stoltenberg posted on X (formerly known as Twitter) to “welcome the Hungarian parliament’s vote to ratify Sweden’s membership in NATO.” He also said, “Sweden’s membership will make us all stronger and safer.” Swedish Prime Minister Ulf Kristersson also took to X (formerly Twitter) to say, “Today is a historic day. The parliaments of all NATO member states have now voted in favour of Swedish accession to NATO. Sweden stands ready to shoulder its responsibility for Euro-Atlantic security.”

Finland officially became a NATO member state in April 2023. Hungary and Türkiye were the final two NATO member states to ratify Finland’s accession as well.