BRUSSELS — NATO is beginning talks this month on the forces and weapons allies would need to defend against a Russian attack — and how they would pay for them.

The talks will set capability targets for 2029, requiring each of NATO’s 32 member countries to provide specific forces and equipment.

The deadline raises the stakes: European officials have warned that Russia could be ready to attack a NATO country by then.

At the same time, the Trump administration is weighing a sharp reduction in U.S. forces in Europe, which could leave the alliance short of troops and critical capabilities with fewer like refueling aircraft, long-range missiles and intelligence, surveillance and reconnaissance assets.

The negotiations will test how much each country is willing to spend, how much Europe can do without the U.S. and whether NATO’s military plans should make greater use of technologies such as robotics and artificial intelligence.

“It’s going to be tough,” said one senior NATO diplomat, who, like others, was granted anonymity to speak freely on the sensitive issue. “Burden sharing, the U.S., how to combine the level of ambition with political priorities … it’s huge.”

NATO allies will begin discussing the broad mandate for the new targets — known as Political Guidance — in the coming days. It’s the first step in a five-part effort called the NATO Defence Planning Process.

“The ambition … is for this to be a transformation cycle and not one that’s just off the shelf,” said French Adm. Pierre Vandier, NATO’s Supreme Allied Commander Transformation and the alliance’s chief for future warfare.

POLITICO spoke to 15 current and former NATO officials and diplomats to get a sense of the five key debates likely to define the negotiations.

1. Deciding on ambition

The most significant issue will be deciding exactly how many troops and military capabilities allies want to provide — known as the level of ambition.

Historically, NATO allies have agreed that beyond the forces needed for major operations, they should have 18 spare brigades — each a unit of about 5,000 soldiers — to carry out smaller crisis-management missions outside alliance territory, like Afghanistan or Kosovo.

But U.S. pressure to hand off more security responsibility to European allies — dubbed NATO 3.0 — could put pressure on allies to reduce or even eliminate requirements for any smaller operations.

Discussions will also cover whether to speed up the process itself in future in response to the furious pace of battlefield innovation, from AI to ground robots. 

Allies are also likely to tackle how to provide conventional military support — like ground troops or aircraft — to nuclear-armed countries like the U.K. and U.S.

“Conventional support … capabilities are absolutely part of the NDPP process,” said Nassima Barrows, NATO’s nuclear policy director, “so that is one of the big messages that we underline as a part of the next [negotiations].”

2. Filling the American gap

Looming over the talks is the Pentagon’s upcoming review of American forces in Europe. Washington earlier this year already pulled assets like strategic bombers, fighter jets, drones, submarines and warships from the pool of forces NATO can draw on.

The review lands in December, midway through the NATO talks, prompting concerns it may delay negotiations. There are worries that the U.S. could pull out assets Europe needs, like heavy transport aircraft.

Washington’s drive to curb its military presence in Europe will set off a scramble among allies to replace its capabilities. That will open discussions on how to share the burden fairly, likely to be very difficult as national budgets are increasingly squeezed.

“Not so long ago, the whole NATO process was … you do the math on what NATO needs, and then when you realize you don’t have everything, the U.S. fills in the gaps,” said Camille Grand, head of the ASD defense lobby and a former senior NATO official. “This is no longer the case.”

One way to tackle that is to shift away from specific weapons requirements to assigning objectives to countries, such as having their forces eliminate Russian command outposts. That could create more flexibility for European allies to who can’t access U.S. weapons like Tomahawk cruise missiles.

“We don’t have to have thousands of Tomahawks … but we can have thousands cheaper, low-cost alternatives,” said Fabrice Pothier, a former NATO policy planning director who is now CEO of the Rasmussen Global consultancy.

3. Regional divides

The focus on Russia is likely to cause friction with allies worried about other threats.

On paper, NATO espouses a “360-degree” approach to security. In practice, the alliance’s focus has shifted eastward since Russia’s full-scale invasion of Ukraine in 2022, and northward in the past year as it set up an Arctic mission (largely in response to pressure from Donald Trump over Greenland).

Some allies would like to see more attention given to the alliance’s southern and southeastern flanks. Issues include Russian mercenary presence in Libya, the potential for weaponized migration and increased submarine activity, alongside drone attacks on vessels in the Black Sea.

“There is too much north,” said a second NATO diplomat. “We should reset.”

4. More drones or more tanks

The drone warfare dominating the frontlines in Ukraine is likely to force a debate on the balance between adding unmanned capabilities and continuing to build up conventional military equipment like tanks and artillery.

Most allies are making plans to increase their use of unmanned systems.

The U.K. this year announced a “hybrid fleet” that leans on autonomous vessels like Type 93 uncrewed underwater vehicles. France has earmarked roughly €8.4 billion for drones and loitering munitions while Germany is establishing its first dedicated drone regiment next year.

Europe’s difficulties in recruiting soldiers also feed into the debate, said Grand. “One thing that is driving everybody in the direction of more unmanned [systems] is we have aging societies — we have a manpower issue.”

Countries also have to figure out how to match Russia’s technological developments without breaking national defense budgets.

Vandier said Russia produces 9 million drones a year, a figure that requires a “pretty radical effort” from the alliance. He suggested one fix could be a subscription-style model for hardware updates to keep weapons systems from becoming obsolete.

5. Learning from Ukraine

Most NATO allies agree that Ukraine contributes to their security thanks to its large and battle-hardened military and its rapid technological developments in air, sea and ground drones, air defenses, missiles, and its advanced Delta battlefield management system.

That has some countries calling for closer military and industrial cooperation, even as others urge caution because the war in Ukraine is different from NATO’s doctrine, which calls for rapid-maneuver warfare, air superiority and standoff precision strikes.

“There are tremendous lessons from the conflict that we need to capture,” NATO’s top commander, U.S. Gen. Alexus Grynkewich, told the European Parliament earlier this month. But “we do not want to fight that kind of war.”

NATO’s top commander U.S. Gen. Alexus Grynkewich on Monday vowed to block, blunt and break any Russian attack as part of a new “Theory of Victory,” and underlined that alliance troops would fight even if U.S. forces were engaged elsewhere.

Speaking at the Warsaw Security Forum, Grynkewich outlined how the 32-member alliance would respond to an invasion of NATO territory as concerns grow that Russia could be capable of attacking a NATO member by the end of the decade.

“Our alliance exists to preserve peace,” he said, “but let there be no doubt: should war come, we will block, blunt any attack, and then, if it does not cease, we will break the forces conducting aggression against us.”

The rare intervention by the four-star general to discuss a military blueprint underscores NATO’s effort to deter Russia. It is also aimed at sending a message of NATO unity after a grueling year for the alliance, which was rocked by Donald Trump’s threats to annex Greenland and infighting over the U.S.-Israeli war in Iran.

Under the three-part blueprint, NATO would initially use land-based troops — buttressed by air, naval, cyber and space capabilities — to stop an assault, targeting attacking forces and preventing them from seizing territory, Grynkewich said.

NATO would then use sensors and autonomous systems among other capabilities to “overwhelm enemy formations … and their advance,” he said, before using “highly effective precision munitions” and unmanned systems if necessary to “break the [enemy] warfighting system” and “everything that supports” it.

Lithuanian Defense Minister Robertas Kaunas said the theory laid out by Grynkewich “will send a strong message to our adversaries that we are going to defend ourselves.”

NATO’s Supreme Allied Commander Europe said he does “not assess that conflict is imminent or inevitable.” But “we will … ensure any attack against any ally proves utterly futile.”

The speech describes a more forceful response if a foe attacks, but its credibility depends on allies having the forces, infrastructure, and coordination to implement the plan.

Asked whether the plan factored in a scenario where the U.S. was engaged elsewhere, Grynkewich said: “It absolutely does account for that, and in fact, it must.”

Under Trump, the U.S. has sought to refocus its military on other priorities such as the Indo-Pacific, homeland security and the Western Hemisphere. U.S. ambassador to NATO Matthew Whitaker said in Warsaw on Monday that Europe only ranks fourth among Washington’s strategic concerns.

The Pentagon has already cut its contributions to NATO crisis forces and is set to unveil a review of U.S. forces in Europe by the end of the year.

“No one should question the commitment of the United States to this alliance,” Grynkewich argued, but added that “ultimately, it’s a political decision about who’s providing troops where.”

Camille Grand, NATO’s former assistant secretary-general for defense investment, said the plan was “a very deliberate effort” to signal that the alliance would be ready to fight with or without large-scale involvement of U.S. forces.

“For my country, fighting with Russians is with or without Americans,” said a separate senior European defense official, who was granted anonymity to speak freely. “We expect them to come, but if they won’t, we will fight anyway.”

Grand added that the blueprint is also an indication that NATO is ready to take a bolder approach toward Moscow by threatening the destruction of its war machine even deep behind the front lines.

That comes as Moscow sent a letter to NATO last month threatening to use its nuclear arsenal if the alliance tried to isolate its Kaliningrad exclave.

Grynkewich warned that NATO would be ready to respond — even with its nuclear arsenal.

“Should an adversary threaten escalation by saber-rattling, or should one actually decide to escalate during conflict, it will not fracture our alliance,” he said. “We should take comfort in our ability to deliver mass effects and the implicit warning that we could match any enemy move up the escalation ladder.”

WARSAW — NATO must modernize its military infrastructure to move forces and equipment from Western to Eastern Europe “where we would expect any future conflict,” U.S. Ambassador to NATO Matthew Whitaker said Monday.

Speaking on a panel at the Warsaw Security Forum, Whitaker’s comments came as Washington reviews its military presence on the continent — with the ambassador saying that Europe ranks fourth among Washington’s strategic priorities, behind homeland security, the Western Hemisphere and the Pacific.

He pointed to outdated military bases, fuel supply chains and agreements governing the stationing of American troops in Europe as areas requiring attention under the ongoing U.S. force posture and basing review.

He emphasized the importance of military mobility and “moving things from the west to the east,” citing discussions with EU Defense Commissioner Andrius Kubilius. European officials warn that Russia could be ready to attack a NATO country by the end of the decade.

Whitaker did not announce any decisions to relocate or withdraw American forces. He nevertheless made clear that Washington is reassessing its global commitments to avoid spreading its military resources too thin.

“Superpowers and great global powers have mostly had challenges when they get overextended,” Whitaker said, adding that U.S. President Donald Trump wants allies to become “capable and not dependent.”

“The United States isn’t stepping back. We’re just asking you to step forward,” he said.

Whitaker also criticized countries that are falling short of their defense-spending commitments.

He said he had recently delivered a “very strong message” to political leaders in Czechia. The country’s defense spending for this year is approximately 1.8% of GDP, falling short of NATO’s current 2% benchmark.

European governments must continue strengthening their armed forces, he argued, warning that the continent still lacks many of the capabilities it needs to defend itself.

Kubilius, meanwhile, stressed the need to reduce Europe’s military dependence on Washington, highlighting EU efforts to develop its own drone defenses, satellite communications and surveillance capabilities.

Polish presidential adviser Marcin Przydacz, also on the panel, urged Western European allies to accelerate defense spending while emphasizing that NATO, rather than the EU, must remain responsible for Europe’s collective defense.