Finland's President Sauli Niinisto and Prime Minister Sanna Marin said on Thursday their country must apply to join the NATO military alliance "without delay", a major policy shift triggered by Russia's invasion of Ukraine.
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 inNATO's membership process that would apply for Helsinki andStockholm:
FINLAND AND SWEDEN SUBMIT MEMBERSHIP REQUEST
NATO officials and diplomats say that ideally the twocountries should submit their requests together - most likely asletters sent to NATO headquarters - to simplify the bureaucraticprocedure.
ALLIED GOVERNMENTS MEET
Representatives of the 30 allies meet in Brussels todiscuss, 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 requestcan be accepted, Finland and Sweden are considered successfuldemocracies with militaries that meet NATO standards.
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.
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 NATObudgets, take part in NATO defence planning and promise torespect rules on classified information.
NATO REPRESENTATIVES MEET AGAIN
The 30 allies would be likely to grant Finland and Swedenmembership, giving them observer status at all alliedmeetings. However, they would still not be covered by NATO'scollective defence guarantee.
RATIFICATION
All allied parliaments must ratify a membership approval bynational governments. This can take anywhere between four monthsto a year, depending on elections, bureaucratic delays andsummer recesses. After the "deposition of the ratification" ofall allies, both Finland and Sweden must also deposit their "instrument of accession" at the U.S. Department of State,finally making both countries NATO allies.
(Reporting by Robin Emmott, Editing by Angus MacSwan and John Stonestreet)