How does a country become part of NATO?

Finland and Sweden have applied to join NATO as Russia’s invasion of Ukraine enters its third month, a conflict that has shaken up European geopolitics.

After almost 70 years of nonalignment, NATO Secretary-General Jens Stoltenberg said Wednesday that both countries have officially applied for membership.

And on Thursday, President Biden welcomed both leaders of the Nordic countries at the White House.

During remarks from the Rose Garden, the American president emphasized the U.S.’s support for the countries’ desire to join the alliance, stating that their membership would make the world more secure. 

“Today, my administration is submitting to the United States Congress reports on NATO accession for both countries, so the Senate can efficiently and quickly move on advising and consenting to the treaty,” he said Thursday. 

The Nordic countries have been neutral for decades, but both are located in close proximity to Russia, and fears of aggression have mounted following the invasion of Ukraine.

Here is how a country becomes a member of NATO: 

What is NATO?

NATO was first created in 1949, in the aftermath of World War II as a military alliance which rests on the principle of “collective defense.”

The principle is enumerated in Article 5 of the alliance’s treaty, which states that an attack on one member of the alliance is considered an attack on all.

According to NATO, the alliance was created with a three-pronged aim – “deterring Soviet expansionism, forbidding the revival of nationalist militarism in Europe through a strong North American presence on the continent, and encouraging European political integration.”

The 12 founding member countries of NATO were Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, Netherlands, Norway, Portugal, the United Kingdom and the United States. 

Membership has now been expanded to 30 countries including: Albania, Lithuania, Bulgaria, Montenegro, Croatia, Czech Republic, Poland, Estonia, Romania, Germany, Slovakia, Greece, Slovenia, Hungary, Spain, Turkey and Latvia. 

The last member to be inducted into the alliance was North Macedonia in 2020. 

Why do countries want to join NATO?

Both Finland and Sweden are members of NATO’s Partnerships for Peace program, which also includes countries from the former Soviet Union.

Following Russia’s invasion of Ukraine, the heads of both the Finnish and Swedish governments issued statements expressing their country’s desire to join the bloc and benefit from the collective defense strategy.

Christopher Skaluba, director at the Atlantic Council’s Transatlantic Security Initiative in Brussels told The Hill that “why Sweden and Finland want to join now is actually exactly the reason people wanted to join in 1949. It was concerned then about the Soviet threat, now the Russian threat.”

Skaluba added that after the Russian troop buildup around Ukraine and the subsequent invasion, Sweden and Finland’s desire to join NATO went from “an idea in the back of someone’s mind to actually happening.”

He added that “it’s directly related to NATO’s original purpose, which is deterrence and defense against the Soviet or Russian threat.” 

Both the Finns and the Swedes possess capable militaries, according to Skaluba, who added that the two countries have defended their own sovereignty for a long time. 

“The Finns in particular have developed a very thoughtful system for territorial defense and so they don’t expect that they’re going to need NATO’s help in defending their territory; they’re not going to ask for a big NATO force presence. But what they want is the insurance policy,” he added.

According to Kristine Berzina, a senior fellow with German Marshall Fund’s Alliance for Securing Democracy, Russia “is showing its colors and its aggressive intentions against Europe, both in its actions in Ukraine, but in the express messages that Russia put out in December and January demanding that Europe turn back time to the military order that existed in the mid 90s.”

What is the NATO membership process?

The NATO membership process has multiple steps. 

First, NATO officially invites potential members to begin accession talks with the alliance.

According to NATO, the accession talks at its headquarters in Brussels, Belgium, are aimed at “obtaining formal confirmation from the invitees of their willingness and ability to meet the political, legal and military obligations and commitments of NATO membership, as laid out in the Washington Treaty and in the Study on NATO Enlargement.”

The countries seeking entrance to the alliance also must agree to undertake any necessary reforms on which their membership hinges. 

The second step in the accession process is a letter of intent where “each invitee country provides confirmation of its acceptance of the obligations and commitments of membership in the form of a letter of intent from each foreign minister addressed to the NATO Secretary General.”

Third, Accession Protocols are created to be included in the Washington Treaty for each invitee. 

According to Skaluba, “every enlargement round at NATO went through the same Accession Protocol where the treaty has been modified.”

Once this is signed by the member countries, they become amendments or additions to the treaty, which “permit the invited countries to become parties to the Treaty.”

Accession protocols then need to be ratified by every NATO member country and by their governments. In the U.S., for example, the accession protocols require the Senate to pass the legislation via a two-thirds majority.

After every member country ratifies the protocols, the NATO secretary-general invites the new countries to accede to the Washington Treaty. 

Only once the countries formally submit their “instruments of accession” to the U.S. State Department will they formally become NATO members.

“Joining NATO was never meant to be this hard, but because the alliance is now so big it just complicates things because you have to get 30 different leaders lined up and on the same page and 30 different legislatures lined up on the same page,” Skaluba added.

How long does the membership process take?

The membership process for any country seeking entry into the alliance can take months. 

The 30 countries each need to vote, and, according to Berzina, “we’re going into a summer where there are political priorities, but other things like recess and election cycles and other priorities that across 30 countries can be disruptive.”

She added that if “things go smoothly,” Finland and Sweden could officially be members by this fall. 

Member states and their legislative calendars

Berzina told The Hill added that the confirmation process for potential NATO members can fall victim to political calendars in the allied countries, both in terms of recesses and elections. 

For the U.S. in particular, Berzina said that it will be symbolically important to move quickly on Finland’s and Sweden’s applications.

“It’s going to be important to move quickly, which of course congressional leaders have expressed the desire to do. That swiftness will signal that the U.S. is committed to voting to this process. If there are bumps in the road, Russia or other adversaries will claim weakness of the United States or of NATO because of a bumpy process.”

She added that the style with which the U.S. Congress manages the NATO ratification process and the seriousness with which Congress takes the process will be watched incredibly closely.

“Any failures and any kind of delays will be costly for the reputation of both the U.S. and NATO,” Berzina added.

What have Finland and Sweden said about joining NATO?

Both Finnish President Sauli Niinistö and Swedish Prime Minister Magdalena Andersson have characterized the Russian invasion of Ukraine as the catalyst for their countries to join the alliance.

The Nordic leaders emphasized during remarks with Biden Thursday that their countries will become strong allies as part of NATO. 

“We are ready to contribute to the security of the whole alliance, making the commitment to mutual security guarantees that being a NATO ally entails. Now that we have taken this first decisive step, it is time for NATO allies to weigh in. We hope for strong support from all allies and for swift ratification of our membership,” Niinistö said. 

“Yesterday, Sweden and Finland submitted our formal requests to join NATO. Russia’s full scale aggression against a sovereign and democratic neighbor was a watershed moment for Sweden and my government has come to the conclusion that the security of the Swedish people will be best protected within the NATO alliance,” Andersson said. 

“Peace and stability in our part of the world is a common security interest for us, for you, and for the rest of Europe. And we stand here today, more united than ever, and we are committed to strengthening our bonds even further, as Sweden is prepared to shoulder its responsibility as an ally in the North Atlantic Treaty Organization,” she added.

Biden, for his part, emphasized that “NATO is relevant. It is effective, and is more needed now than ever.” 

A Kremlin spokesman said last Thursday that Finland joining NATO would threaten Russian security and do nothing for the security alliance. 

Finland and Sweden are unique

Skaluba said that Finland’s and Sweden’s bids for membership to NATO is “unique,” compared to countries that have applied in the past. 

Both Finland and Sweden meet most of the requirements for entrance into the alliance economically, militarily and governmentally. 

“Every one of the countries that joined NATO at the end of the Cold War were all either former Soviet countries or Warsaw Pact countries. So there were long reforms required by each of them on the economic front ,on the democratic front, but especially on the military front, to make them eligible for NATO membership. The process in each of those cases had a long lead time, and took years,” he added.

In recent history, Finland and Sweden have remained neutral, and never aligned with the Soviet Union or Russia. 

“They had Western philosophies on military matters. They were members of the EU starting in 1995, they have sophisticated militaries that operate at the very high end. They both fly advanced fighter jets and of course this is happening during a crisis,” he added.

According to Skaluba, “these circumstances are just unique, and NATO isn’t following the playbook of the last 30 years” when it comes to their membership.

Turkey could be a speed bump for Sweden and Finland

Turkey threw a last-minute wrench into what was shaping up to be a swift application process for the Nordic countries. 

Turkish President Recep Tayyip Erdoğan claimed that Sweden and Finland backed the PKK, a Kurdish separatist group that has been fighting the Turkish government for decades.

The opposition from Erdoğan has come as somewhat of a surprise. 

Erdoğan had reportedly told Niinistö in early April that he was “supportive”.

“Turkey’s statements have changed very quickly and hardened in recent days. But I am sure that we will resolve the situation with constructive talks,” Niinistö said on Tuesday. 

“He said that the Finnish membership should be assessed favorably. Now it seems that there are different opinions. We must continue to discuss.”