It seems clear that Finland and Sweden will announce their intention to seek NATO membership by mid-May. This leaves enough time to complete membership negotiations by the end of June, when the NATO Summit will be held in Madrid. If all goes according to plan, NATO will have two new members by the end of 2022.

How did we get here, and what does this mean for Finland, Sweden, NATO and security in Europe?

This dramatic change in Finland’s and Sweden’s security policies has few historical analogies. Yet, history explains why it took both countries three decades following their accession to the EU to also seek membership of Europe’s collective defence organisation.

For Sweden the decreased sense of threat in the post-cold war era, the strong but slightly ahistorical self-identity as a ‘neutral’ country, and an expectation that war was forever banished from the region had simply made NATO membership seem unnecessary. Yet, as Sweden increasingly cooperated with NATO through the first decade of the 2000s, opposition to Swedish NATO membership decreased. From 2006 onwards polls regarding membership have fluctuated with opposition ranging from thirty to fifty percent while twenty to fifty percent of the population have supported membership. In recent years approximately a third each have opposed, supported and been undecided about Swedish NATO membership.

In Finland’s case, the public’s opposition to Finnish NATO membership has been much more stable, despite equivalent levels and types of cooperation with NATO. Since the late 1990s sixty to seventy percent of the population has been against Finnish NATO membership, while twenty to thirty percent have supported the idea. This stability is remarkable but at least partially explained through historical lessons to do with seeking to avoid becoming involved in great power competitions and an almost fatalistic expectation that no one would ever come to Finland’s assistance. A frequently quoted plaque by the King’s Gate on Suomenlinna fortress outside Helsinki reminds the reader to ‘stand here on your own feet and do not trust/expect foreign assistance’. This combined with the Finnish national memory of during the Winter War being left completely alone against the Soviet Union (factually not entirely correct), left many Finns with doubts about whether anyone would come to aid Finland — allied or not. The view that Finns have throughout the centuries been drawn into wars by the West (as part of the Swedish kingdom) or forced into wars by Russia, contributed to the idea that it was best to avoid becoming party to great power competition; and, during the cold war NATO was certainly seen as a part of this competition.

Although the Finnish view of the regional security situation changed dramatically in 2014, the stability in public opinion is not entirely surprising, considering the aforementioned history, concerns about Russia’s potential response (really an evaluation on whether the potential increase in defence assistance/deterrence would outweigh Russia’s reactions), and a belief in Finland’s own robust national defence capability.

Considering this history, it came as a genuine surprise to first the Finnish and then the Swedish political decision makers, that it was the Finnish population that effectively forced both countries to first consider and then likely seek NATO membership in 2022. Having held a largely stable opinion opposing NATO membership for two decades, the Finnish population has in the space of four months completely reversed its view on the desirability of NATO membership. By the end of April nearly seven in ten Finns wanted to see Finland seek NATO membership, with nary one in ten opposing it.

In Finland the political process and the debate over NATO membership have proceeded blindingly quickly. In early April, following a visit to the White House, Finnish President Niinistö presented two potential paths for Finland to address its perceived security deficit: NATO membership or deepening cooperation with the United States and Sweden. By the April 13, the Finnish government had presented an update to its foreign and security policy report. While the update did not make a formal argument for Finnish NATO membership, the intent was clear: to provide the policy arguments for membership and indicate an envisioned process for seeking NATO membership. In Sweden, the process has been less clear, though an equivalent government report is expected on May 13, the day after the Finnish President is widely expected to announce his support for seeking Finnish membership in NATO.

When presenting the Finnish government’s new report, foreign minister Pekka Haavisto laid out the logic for a Finnish NATO membership application in an explicit and clear way: The application was not about solving Finland’s potential security issues in 2022, but rather about anticipating problems arising in the coming years and decades. Of particular concern was Russia’s increased use of military force, ability to mobilise and quickly mass hundreds of thousands of soldiers at a neighbour’s border, and looser talk about use of non-conventional/nuclear weapons. Due to the nature of these threats, Haavisto argued, including nuclear weapons which Finland on its own could not reasonably deter, Finland needed increased deterrence including a nuclear component and the potential for collective defence efforts — requirements that only NATO membership fulfils.

While both Sweden and Finland are not even NATO observer members as of writing, the national histories, views on defence and reasons for seeking NATO membership suggest what kinds of NATO members both might become. Finland and Sweden will want to contribute to strengthening collective deterrence and ‘peace time’ operations, while focusing the bulk of their defence efforts on the Baltic Sea and Arctic regions. When both become members of NATO, it will be possible to reimagine NATO’s defence plans for the entire region. Finland’s and Sweden’s robust military capabilities, long experience of operating in a challenging regional environment, and geographic location will contribute to the potential for collective defence. Both can also be expected to participate in NATO’s efforts to increase deterrence through contributions to the enhanced Forward Presence (eFP) battalions, which are located in the eastern most member states and consist of forces from multiple NATO members, as well as the the Baltic Air Policing mission.

As Finnish politicians have made clear that gaining nuclear deterrence is a reason to seek membership, it should only be expected that Finland would not place any additional nuclear weapons related restrictions on itself. Neither does it seem likely Finland would place ‘Norway-like’ limits on NATO member forces or basing, nor that it would ask for the permanent stationing of other NATO members forces on its soil, with the exception of a NATO Force Integration Unit (NFIU). The purpose of the NIFU is to facilitate the logistics of receiving member forces into the country in question, either for exercises, increased deterrence or collective defence efforts.

For European security, Finland’s and Sweden’s NATO membership is an unalloyed good thing, despite the loud protestations by Russia. For both countries, while they have been politically and economically allied through their EU membership for over a quarter century, NATO membership will require a change in national security policy cultures, in recognising what collective security means, both in terms of the responsibilities and benefits it brings.