While Finland joined NATO as a full member on Tuesday, fellow aspirant Sweden’s application is still pending, which is a short-lived but "embarrassing" delay that could render the Nordic country more vulnerable and cause issues within NATO, according to experts speaking to Agence France-Presse (AFP).

Finland became the 31st member of the military alliance after securing the last two ratifications needed from Hungary and Türkiye last week.

Finland and Sweden abandoned decades of military nonalignment and applied to join NATO in the wake of Russia's invasion of Ukraine, stressing they wanted to walk in lockstep.

But Ankara and Budapest have refused to ratify Sweden's bid following a series of disputes and primarily security concerns on the part of Türkiye.

Whether the delay becomes a real problem depends on how long it lasts, experts said.

"If we are talking about months, it's embarrassing, but not really a major problem," Robert Dalsjo, an analyst at the Swedish Defense Research Institute (FOI), told AFP.

However, if the process drags on, it could complicate both Sweden's and NATO's defense planning in the region.

Jacob Westberg, an associate professor of War Studies at Sweden's Defense University, noted that it isn't possible for "non-member states to fully participate in NATO's defense planning."

That leaves Sweden out of action.

For example, if military supplies needed to be quickly deployed to the Baltic states and Finland, east of the Baltic Sea, "then it would be very practical to be able to operate out of Swedish territory," Westberg said.

He added that a delay also means that NATO will not be able to count on Swedish military assets – such as its fleet of submarines in the Baltic Sea and JAS Gripen fighter jets.

Analysts have long pointed to Sweden's geographical significance in the event of a conflict in Northern Europe, with the island of Gotland sometimes described as an "unsinkable aircraft carrier" in the Baltic.

Cracks

In addition to planning woes, Anna Wieslander, director for Northern Europe at the think tank Atlantic Council, said the disagreement on Sweden could expose cracks within the alliance.

"If NATO doesn't deliver on Sweden becoming a member, then NATO will appear weakened," Wieslander said.

Lingering divisions could ultimately affect how NATO supports Ukraine, she added.

"That which has been the alliance's greatest strength... in the Ukraine crisis, has been that members can move forward together and remain united," Wieslander said.

New members need to be unanimously ratified by all members of the alliance, and Sweden still faces opposition from Ankara and Budapest.

It has especially angered Türkiye by failing to extradite dozens of suspects that belong to terrorist groups like the PKK/YPG and the Gülenist Terror Group (FETÖ), which was behind the failed 2016 coup attempt that left 251 dead in Türkiye.

The PKK is listed as a terrorist organization by Türkiye, the European Union, the United Kingdom and the United States, and is responsible for the deaths of 40,000 people, including women, children and infants.

In dispersing accusations of deliberately pushing the bloc into a deadlock, Ankara has repeatedly expressed its support for NATO’s open-door policy, with several Turkish officials, including President Recep Tayyip Erdoğan, stressing "effective cooperation" against terrorism as a "must" with Sweden’s bid.

Stockholm has repeatedly drawn Türkiye’s ire, however, by largely overlooking its "legitimate" security concerns regarding terrorists and allowing their sympathizers to hold anti-Türkiye rallies.

NATO diplomats hope Erdoğan will become more amenable if he wins the elections next month while Stockholm claims it's "ambitious" to become a NATO member at the bloc’s next summit in Vilnius this July.

But Ankara remains resolute that Sweden must first fulfill its commitments under the deal and take concrete action, with Erdoğan saying, "Stockholm's NATO membership will directly rely on their measures."

'Look at the map!'

In a speech in late March, Sweden's Prime Minister Ulf Kristersson said his country was "safer with Finland inside" NATO.

"Look at the map! We'll be surrounded by NATO countries," Kristersson said, stressing the security assurances also offered by several NATO members, including the U.S. and Britain.

As a non-member, Sweden is not covered by the security guarantees of NATO's Article 5 on collective defense, which states that an attack on one member is an attack on all.

Westberg also noted that Kristersson's evaluation clashed with the one Sweden's parliament presented in a security policy assessment before applying to NATO, which specifically highlighted the risks that Sweden would face if only Finland applied.

As the only Nordic country outside NATO, Sweden would become a "specific military-strategic interest for Russia in the event of a conflict."

"Our military and security policy vulnerability, and exposure, would increase," the report said.

In particular, Westberg noted that the common defense planning between Sweden and Finland that has developed since 2014 would not be able to continue in "the same way."

As a NATO member, Finland will have to prioritize its obligations toward the alliance, Westberg explained.

While Sweden has some 200 years of experience in staying out of military alliances, the researcher also noted that the country does not have nearly the military capabilities it had during the Cold War.

In the 1950s, Sweden had a defense budget totaling around 4% of its gross domestic product (GDP), discouraging a potential attack from the Soviet Union by making it too costly.

Following decades of cuts, the country is once again rearming, but to a lesser degree.

Last year, Sweden announced plans to boost spending to 2% of GDP "as soon as possible."

Its haste could come in handy too as Finland’s accession has elicited a cross-reaction from Moscow this week as Kremlin warned it would take "military and other steps" to respond to the NATO expansion.

Describing Helsinki’s new military alignment as an "escalation," and an "encroachment on Russia’s security and national interests," Moscow said it will take "concrete defense-building steps considering whether NATO infrastructure and attack weapons will be deployed within Finland."