Finland, Sweden are set to apply for Nato membership. What happens next?

Sweden’s ruling Social Democrats are expected to decide on Sunday whether to overturn decades of opposition to Nato membership, a move that would almost certainly lead to Sweden also asking to join the 30-nation alliance.

The two countries had for decades held the belief that peace was best kept by not publicly choosing sides.

Any accession process is expected to be much shorter than previous applications to join the alliance, which was founded in 1949.

While there is no set time frame, here are the steps in Nato’s membership process that would apply for Helsinki and Stockholm:

1. Finland and Sweden submit membership request

Nato officials and diplomats say that ideally the two countries should submit their requests together – most likely as letters sent to Nato headquarters – to simplify the bureaucratic procedure.

2. Allied governments meet

Representatives of the 30 allies meet in Brussels to discuss, and most probably accept, the membership request.

While many other aspirants, such as Ukraine and Georgia, have been asked to carry out reforms before a request can be accepted, Finland and Sweden are considered successful democracies with militaries that meet Nato standards.

3. Membership talks begin; ‘marriage vows’ are made

This is likely to happen in Brussels at Nato headquarters, taking as little as one day for each country, assuming compliance with the terms of Nato’s founding Washington Treaty.

The two countries are already considered to “contribute to the security of the North Atlantic area”, as the treaty demands.

In response to Russia’s invasion of #Ukraine, NATO has up to 30 aircraft on patrol at any moment.

To deter any potential aggression against Allies, #NATO is deploying an unprecedented mix of fighter jets, reconnaissance aircraft and support planes ✈️ pic.twitter.com/zQW35paSv8

— NATO (@NATO) May 10, 2022

Known informally as Nato’s “marriage vows”, officials from Helsinki and Stockholm would be questioned as to whether they would uphold Nato’s collective defence pledge that an attack on one ally is an attack on all.

They would also have to agree to pay their share of Nato budgets, take part in Nato defence planning and promise to respect rules on classified information.

Nato representatives meet again

The 30 allies would be likely to grant Finland and Sweden membership, giving them observer status at all allied meetings. However, they would still not be covered by Nato’s collective defence guarantee.

4. Ratification

All allied parliaments must ratify a membership approval by national governments. This can take anywhere between four months to a year, depending on elections, bureaucratic delays and summer recesses. After the “deposition of the ratification” of all allies, both Finland and Sweden must also deposit their “instrument of accession” at the US Department of State, finally making both countries Nato allies.