Finnish President Sauli Niinisto is expected on Thursday to say whether his country should join the NATO alliance, with Sweden following suit with its decision in the coming days.
Russia's invasion of Ukraine has pushed Finland and Swedento the verge of applying for NATO membership and abandoning abelief held for decades that peace was best kept by not publiclychoosing sides.
Both countries are close NATO partners, having taken part in allied exercises for years. Any accession process is expected to be much shorter than previous applications to join the alliance since the 1950s. NATO 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:
FINLAND AND SWEDEN SUBMIT A 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.
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 membership request can be accepted, Finland and Sweden are considered successful democracies 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, which agree to respect 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 answer questions on 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 likely grant Finland and Sweden membership of NATO, giving them observer status at all allied meetings. However, they would still not be covered by NATO's collective defence guarantee.
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 its "instrument of accession" at the U.S. Department of State, finally making both countries NATO allies.
(Reporting by Robin Emmott; Editing by Alison Williams)