United States President Joe Biden will host leaders of NATO in Washington, DC, this week as the military alliance marks 75 years since its formation amid security threats arising from the Russian invasion of Ukraine and China’s growing assertiveness in the Asia Pacific.

The summit, which will run from Tuesday to Thursday, is largely expected to focus on reassuring Ukraine of the alliance’s unwavering support after Russia pummeled Ukrainian cities with missiles on Monday, hitting a children’s hospital in Kyiv. At least 31 people were killed in the Russian attacks.

It will be the first international appearance for new British Prime Minister Keir Starmer, whose Labour Party won last week’s general election in a landslide. President Emmanuel Macron of France, who faces a political dilemma after a leftist bloc emerged as the largest player in the National Assembly after Sunday’s elections, will also be present.

NATO was formed during the Cold War in 1949 to counter threats posed by the Soviet Union. Article 5 of its founding treaty commits members to a collective military defence, under which an attack on one member is considered an attack on all, and effectively keeps its enemies at bay. The alliance has since grown from  12 members to 32 with its newest member, Sweden, joining in March.

Here’s what we know about who is attending the summit and what will top the agenda:

Who will be there?

Biden will host outgoing NATO Secretary-General Jens Stoltenberg and the leaders of other NATO countries, who will include German Chancellor Olaf Scholz, Italian Prime Minister Giorgia Meloni, Canadian Prime Minister Justin Trudeau and, for the first time, Swedish Prime Minister Ulf Kristersson.

Leaders from NATO partner countries will also be present. Partner nations are restricted from joining the alliance because of Article 10 of its treaty, which limits new members to Europe. Leaders of partner countries expected at the summit include:

• Ukrainian President Volodymr Zelenskyy
• Prime Minister Fumio Kishida of Japan
• Australian Prime Minister Anthony Albanese
• President Yoon Suk-yeol of South Korea
• New Zealand Prime Minister Christopher Luxon
• European Union leaders, including Charles Michel, head of the European Council, and European Commission President Ursula von der Leyen

Foreign and defence ministers as well as other senior officials from NATO countries and their partners will also be present.

What’s on the agenda?

Support for Ukraine: The biggest topic on the agenda is supporting Ukraine. In a White House news briefing on Monday, Biden security adviser Mike Carpenter told reporters that NATO allies are expected to announce new support for Ukraine, including renewed funding of 40 billion euros ($43.2bn) over the next year in addition to millions pledged bilaterally by NATO countries. Allies are also expected to announce the launch of a military command station in Germany that is expected to boost Ukrainian forces with training and equipment.

The issue of NATO membership for Ukraine will be a hot button topic. Ukraine’s ambitions to join have been bogged down by internal reform requirements and the alliance’s fears of escalating tensions with Russia. While Ukraine’s membership is still far from getting a green light, NATO allies have in recent months ramped up support for the war-ravaged country.

NATO leaders, including Biden, have in the past promised not to drag the alliance into the Russia-Ukraine conflict and have restricted Ukraine from using weapons provided by its allies on targets inside Russia. But in May, Biden for the first time permitted Kyiv to use US-supplied weapons to strike targets inside Russia close to Kharkiv, Ukraine’s second-largest city, which sits 40km (25 miles) from the Russian border. At the summit, the alliance will “recognise Ukraine’s vital ongoing reform efforts and demonstrate allied support for Ukraine on its path to NATO membership”, Carpenter said.

Defence spending: The US is NATO’s financial heavy lifter, and it and NATO itself have long tried to boost military spending from other member countries. Progress made on a 2014 target for each country to spend at least 2 percent of its gross domestic product (GDP) on defence by 2024 is expected to be reviewed. US officials said 23 members are now hitting that target, up from nine in 2021, after the commitment was reaffirmed at last year’s summit in Vilnius, Lithuania.

However, eyes will be on the countries who have not met the pledge, particularly Canada, a richer country among the members failing to meet the target. In May, 23 US senators from both the Democratic and Republican parties penned a letter to Trudeau, voicing their “disappointment” after the country revealed its defence spending would reach only 1.7 percent of its GDP by 2029. Canadian Defence Minister Bill Blair responded to the letter by saying: “Canada is on a very strong upward trajectory in defence spending” and “we know we’ve got work to do.” Spain, Italy and Portugal are also among the lowest spenders.

China: NATO will also seek to reassure its Asia-Pacific partners – Australia, Japan and South Korea – of the alliance’s continued support against an increasingly aggressive China. Beijing has been accused of boosting its military presence in the disputed South China Sea, an important global trade route, nearly all of which China lays claim to. Numerous other governments in the region, including the Philippines and Taiwan, also claim territory there and contest China’s growing assertiveness.

NATO members rely on trade passing through the region and have an interest in stabilising the route as well as in protecting Taiwan, a key ally of Washington that China also lays claim to. Recent confrontations with Manila have also caused alarm. In June, Chinese motorboats rammed and then boarded Philippine navy inflatable boats trying to transfer food to a Philippine outpost on the Second Thomas Shoal, a submerged reef claimed by both countries. That episode led to several military personnel being injured and was the most intense the two countries have engaged in in years.

The Philippines signed a defence pact with Japan on Monday that will allow the deployment of soldiers on each other’s soil. Washington has also boosted its military ties with Manila.

China’s deepening friendship with Russia is also of concern for the alliance, particularly as Beijing has been accused of providing dual-use material to the Russian military that US officials said has allowed Moscow to target Ukraine and poses a threat to European security.

NATO officials said in 2023 that Russia imported 90 percent of its microelectronics used to manufacture missiles, tanks and aircraft from China. Beijing, meanwhile, has repeatedly denied these claims. NATO allies at the 2023 summit in Vilnius declared that China’s “stated ambitions and coercive policies challenge our interests, security and values”.

What’s at stake for Biden?

It will not be an official topic, but US domestic politics is likely to affect the mood of the summit. Biden’s campaign for re-election in November faces a massive crisis, and polls show President Donald Trump, a continual critic of NATO while he was in the White House, widening his lead against the incumbent. Biden’s poor performance at a presidential debate with Trump in late June has unleashed questions about his mental fitness and prompted calls for him to make way for another candidate.

Members of Biden’s Democratic Party are floating several names, including Vice President Kamala Harris and several state governors, as possible replacements.

NATO allies, meanwhile, are considering the potential ramifications of an unfriendly Trump presidency. Trump has threatened to pull the US, a founding NATO member and its biggest funder, from the organisation and is staunchly against providing more aid to Ukraine. In a March interview, Trump said he will not quit NATO but reiterated that the European partners need to drastically increase their military spending.

Even if the US does not end up leaving the alliance, experts said Trump is likely to severely downgrade the US role in the organisation.

Can the the alliance hide disunity among its members?

Although the NATO summit will try to demonstrate strength and unity amid rising security threat from Russia and China, the internal rifts among its member states will be hard to mask.

Turkey and Hungary were the hold-out members that delayed Finland’s and Sweden’s bids to join NATO. The two are also among only a handful of NATO members that remain friendly with Russia.

Hungarian Prime Minister Viktor Orban’s ties with Moscow are especially likely to drive tensions. Orban, who currently holds the rotating presidency of the European Council, has repeatedly blocked EU aid to Ukraine and has continued to trade with Russia.

Since taking the EU presidency, Orban has tried to paint himself as a peacemaker. Last week, he met with Russian President Vladimir Putin in Moscow, a meeting that has come under heavy criticism by EU leaders and Kyiv. Orban called the trip a “peace mission” that followed a visit to Ukraine. One White House official said Washington did not see the visit as “helpful” or “constructive”.

Orban also met with Chinese President Xi Jinping on Tuesday to discuss ending the war in Ukraine. He described China as a stabilising force amid global turbulence and praised its “constructive and important” peace initiatives.

These include a six-point peace plan that Beijing issued with Brazil in May to end the war. Russia agreed to the plan, but Ukraine said it did not meet its conditions, including for Russian troops to withdraw from the country.