Leaders of the 31 countries that comprise the North Atlantic Treaty Organization will meet in Vilnius, Lithuania, for a two-day summit starting Tuesday, as Russia’s war in Ukraine is near its 18th month.

The meeting is held at a crucial moment in the conflict. NATO wants to bolster Kyiv with new munitions – including US-supplied cluster bombs – for its counteroffensive and assess the impact of the aborted June mutiny by Wagner Group chief Yevgeniy Prigozhin on Russia’s leadership and operations.

But the Alliance is also grappling with internal disputes over Turkey’s reluctance to approve Sweden’s accession and whether to pave the way for Ukraine’s eventual accession.

Nevertheless, the assembled leaders – including US President Biden, who remains the most powerful figure in the alliance – are keen to use this week’s meeting to point out that the Ukraine conflict has done nothing but strengthen NATO. Biden has also planned a high-level meeting on climate with Britain’s King Charles III and a meeting with the Nordic nations hosted by Finland, the alliance’s newest member.

Here’s what to see when world leaders arrive in Vilnius:

Accession of Sweden

Turkish President Recep Tayyip Erdogan is scheduled to meet Swedish Prime Minister Ulf Kristersson on Monday before the summit in a last-ditch effort by the Nordic country to convince Ankara to be allowed into NATO.

Turkey has stated that its opposition stems from concerns that Sweden is not doing enough to crack down on Kurdish separatist groups, which Ankara considers terrorist organizations.

Erdogan has also expressed his desire to meet with Biden – US National Security Adviser Jake Sullivan has said he expects the two to speak at the summit – and to buy US F-16 fighter jets for his military.

Biden acknowledged that “Turkey is looking to modernize F-16s” and suggested that it could be part of a move by the United States to bolster neighboring Greece militarily as well. “It’s up for grabs,” he said in a July 7 interview with CNN’s Fareed Zakaria GPS. “It’s not done.”

He renewed his support for Sweden’s entry into NATO, adding: “I am optimistic.”

Although it is too late for Turkey and Hungary to ratify Sweden’s accession before the summit, the allies remain hopeful that both sides can announce that they have broken the deadlock.

On Thursday, NATO Secretary Jens Stoltenberg was optimistic, saying Sweden’s accession was within reach and a “positive decision” was possible at the summit. A day later, Erdogan said that Turkey could not trust a country where “terrorists roam freely through its streets.”

help Ukraine

Ukraine will be a key issue, and President Volodymyr Zelensky is scheduled to participate in the summit.

The 31-nation NATO is expected to offer Kyiv a pledge of long-term support aimed at closer ties without immediately making it a member, as the bloc’s Article 5 security guarantees could drag the allies into war with Russia against Ukraine. The United States on Friday announced an $800 million package that includes controversial cluster munitions, which some NATO allies have banned on humanitarian grounds related to unexploded ordnance.

Zelenskiy has called for the summit to send clear signals of support for his country’s accession, urging allies to offer a more concrete perspective beyond a 15-year-old declaration that Ukraine will eventually join.

Allies are grappling with how to address the issue in the summit declaration, with some eastern NATO members pushing for a more concrete path. Countries like the United States and Germany have preferred to focus on immediate aid. One option could be to declare that Ukraine does not need a Membership Action Plan to speed up the country’s entry when allies finally decide to invite it to join.

The Vilnius package will enhance the formal status of NATO’s relationship with Ukraine by creating a new NATO-Ukraine Council, which will allow Ukraine to participate directly in broader discussions on alliance security and consult with its allies about your security concerns.

NATO leaders are also expected to agree to a fund of 500 million euros a year in non-lethal aid to help Ukraine modernize its military. On the summit’s sidelines, some allies are expected to pledge bilateral security guarantees to Ukraine, pledging to ensure its armed forces are well-equipped and trained to discourage Russia from re-invading the country after the war.

defense spending

NATO leaders plan to sign a new defense spending commitment, whereby they agree to allocate “at least” 2% of gross domestic product to defense. The deal expands on the alliance’s previous aspirational goal of reaching 2% and underscores pledges to spend more after the invasion of Ukraine.

But many countries, such as Luxembourg, Canada and Italy, continue to struggle to comply with the old guideline. Only 11 of the 31 allies are expected to meet the 2% target this year, according to estimates released by NATO on Friday.

The Alliance is also expected to approve three regional defense plans for the first time since the end of the Cold War, detailing how countries will defend their territory should it come under attack by Russia or terrorist groups.

The leaders are also expected to approve a defense industry action plan aimed at boosting defense production as Ukraine consumes artillery ammunition faster than allies can produce it.

general secretary

One of the biggest questions facing the leaders meeting in Vilnius is who will lead their group in the future, especially given the threat of a protracted conflict in Ukraine.

Last week, Stoltenberg agreed to continue for another year – his fourth extension in office – despite having publicly stated that he did not want to extend his term.

But neither of the leading candidates to replace him – Danish Prime Minister Mette Frederiksen or Britain’s Defense Chief Ben Wallace – seems able to garner enough consensus to secure the job, and the US ultimately refrained from publicly endorsing a candidate. Biden’s top priority was maintaining unity within the alliance, according to a person familiar with the matter.

Stoltenberg’s return has fueled speculation that European Commission President Ursula von der Leyen, a former German defense minister, will be the candidate for the job when her term ends next year.

special relationship

Biden’s visit to the UK, his second in three months, is largely seen as a reconciliation trip following his refusal to attend Charles III’s coronation in May.

Although Biden is scheduled to visit 10 Downing Street to meet Prime Minister Rishi Sunak before traveling to Windsor Castle, he is expected to be on the ground for less than a day. During their royal hearing, Biden and the British monarch are expected to unveil a two-pronged effort toward a mutual passion: enlisting private companies to help finance projects that can reduce climate change.

Britons are hoping Biden will reaffirm his commitment to a series of small trade, military and technology deals that Sunak touted as the “Atlantic Declaration” during his visit to the White House last month.

Biden could also put Sunak on the spot by pushing him to resolve the impasse over the implementation of the power-sharing provisions of the Good Friday Agreement. A strong pledge of military support for Ukraine is to be expected, as the UK is the second country, after the US, to supply arms and aid to the Ukrainians.

Natalia Drozdiak and Justin Sink