NATO aims to boost defenses against drones, hacking and sabotage

That makes the work of preparing for battle more important than ever. Addressing the challenge of protecting and mobilizing forces inside the North Atlantic Treaty Organization’s homeland is rising on the alliance’s must-do list.

“If World War III breaks out on the European continent, what’s the first shot?" said U.S. Ambassador to NATO Matthew Whitaker recently. “Is it going to be Russian tanks invading Poland, or is it going to be a cyberattack on one of our allies or a challenge on some infrastructure?"

The question hangs over preparations for NATO’s annual summit in The Hague starting on Tuesday. Funding for readiness and resilience will be high on leaders’ agenda and a core element of hitting a spending target set by President Trump.

Trump said early this year that NATO allies should spend 5% of gross domestic product on defense, up from 2%. NATO Secretary-General Mark Rutte, who was already urging an increase to 3.5%, seized the moment to push for spending on long-overlooked areas such as mobility and resilience.

Rutte in March proposed topping up traditional NATO defense outlays, such as weapons and salaries, with a further 1.5% of GDP for the military-related spending. Leaders hope the proposal will be approved at the summit.

Most Europeans are endorsing Trump’s target because they want to avoid giving him a reason to disengage from NATO. And they have come to understand that readying military forces is never easy, even in peacetime. Forces being mobilized for battle are prime targets for attack. So is infrastructure, ranging from roads and ports to phone lines and power plants.

One thing no commander wants to run out of is options, a military adage holds—and adversaries have more ways than ever of foreclosing options. Planners must consider wild cards from old-style sabotage to innovations including cyberattacks and drone strikes.

“If China can shut off the power to our data centers, then maybe they don’t need to sink our aircraft carriers," said retired Army Lt. Gen. Douglas Lute, a former U.S. ambassador to NATO.

Western military planners haven’t faced serious threats to logistics since World War II. Russia’s invasion of Ukraine and the risk of further conflict changes that. Now logisticians, who focus on mobilizing troops and sustaining battles, must refine their plans with an eye to homeland security and the risk that adversaries will do everything possible to stop defending forces from leaving bases and engaging in combat. Israeli special forces operating inside Iran targeted its mobile air-defense vehicles and other equipment at the start of Israel’s attack on June 13.

“It’s going to be a fight to get to the fight," said retired U.S. Air Force Gen. Jacqueline Van Ovost, former head of U.S. Transportation Command, last year about a potential future conflict. “The homeland is no longer a sanctuary."

Van Ovost warned of GPS interference to impede navigation cyberattacks as among her biggest fears.

Until recently, NATO’s 32 members focused on raising military spending to meet the needs of new battle plans that commanders have drafted since Russia’s large-scale invasion of Ukraine in 2022. Those plans, assembled by U.S. Army Gen. Christopher Cavoli, NATO’s supreme allied commander for Europe, will require members to spend about 3.5% of their national economic output on arms and defense, up from a target of 2% set in 2014.

Combatants and their weapons need lots of supporting mechanics, medics, equipment and other backup to operate. Military gear is heavy and cumbersome, requiring reinforced bridges and high overpasses to move across civilian transportation arteries.

When more than 2,100 NATO troops deployed to Poland and the Baltic states in 2015, after Russia seized the Crimean Peninsula from Ukraine, equipment loaded on road and rail convoys lost antennas and had other small accidents because former Warsaw Pact infrastructure was built to different standards from NATO’s, said retired Army Maj. Gen. Gordon Davis, who served as the alliance’s top official handling defense investment.

Allocating funding for nonlethal areas including infrastructure and resilience “will help incentivize focused investment on things that make a difference for European defense," Davis said.

When the Netherlands started ramping up defense investment in recent years, its priority was logistics and medical facilities—areas badly depleted by years of cuts, said Dutch Chief of Defense Gen. Onno Eichelsheim.

“You have to build resilience in your roads, railroads and waterways," increasing transportation options, he said. “It is costly and it is a lot of work."

Adding to complexity: Homeland security isn’t in military hands during peacetime, and law-enforcement agencies rarely coordinate with armed forces. Sabotage and cyberattacks on private-sector assets have only recently come to be seen as national-security threats.

U.S. authorities have accused China of planting malware in systems running port cranes that would be vital in a military mobilization. The Pentagon has forbidden use of foreign ports employing a Chinese cargo-data network, Logink, which they fear could be repurposed for espionage or to disrupt military logistics.

In Europe, authorities have faced what they suspect are Russian efforts to scope out and attack current military support to Ukraine and future NATO mobilization networks.

A Russian “threat actor" known as Fancy Bear targets Europe’s transportation sector, including air-traffic-control systems and maritime organizations, largely linked to support for Ukraine, according to Norma Cyber, a nonprofit organization that Norwegian shippers established to support members’ cyber resilience.

Write to Daniel Michaels at Dan.Michaels@wsj.com