By LORNE COOK

BRUSSELS (AP) — In the year after Russia launched outright war on Ukraine, NATO leaders approved a set of military plans designed to repel an invasion of Europe. It was the biggest shake-up of the alliance’s defense readiness preparations since the Cold War.

The secret plans set out how Western allies would defend NATO territory from the Atlantic to the Arctic, through the Baltic region and Central Europe, down to the Mediterranean Sea. Up to 300,000 troops would move to its eastern flank within 30 days, many of them American. That would climb to 800,000 within six months.

But the Trump administration warned last month that U.S. priorities lie elsewhere. Europe must take care of its own security, and those goals now seem questionable. Mustering just 30,000 European troops to police any future peace in Ukraine is proving a challenge.

Billions of euros are being shifted to military budgets, but only slowly, and the Europeans are struggling to fire up production in their defense industries.

Beyond funding, tens of thousands more European citizens might have to complete military service, and time is of the essence. NATO Secretary-General Mark Rutte has warned that Russian forces could be capable of launching an attack on European territory in 2030.

Concerned about Russia’s intentions, Polish Prime Minister Donald Tusk wants to introduce large-scale military training for every adult male, and double the size of Poland’s army to around 500,000 soldiers.

“If Ukraine loses the war or if it accepts the terms of peace, armistice or capitulation … then, without a doubt — and we can all agree on that — Poland will find itself in a much more difficult geopolitical situation,” Tusk warned lawmakers last week.

The scale of Europe’s military personnel shortage

The Stockholm International Peace Research Institute estimates that Europe, including the U.K., has almost 1.5 million active duty personnel. But many can’t be deployed on a battlefield, and those who can are hard to use effectively without a centralized command system.

The number of Russian troops in Ukraine at the end of 2024 was estimated to be around 700,000.

NATO troops are controlled by a U.S. general, using American air transport and logistics.

Analysts say that in the event of a Russian attack, NATO’s top military officer would probably dispatch around 200,000 U.S. troops to Europe to build on the 100,000 U.S. military personnel already based there.

With the Americans out of the picture, “a realistic estimate may therefore be that an increase in European capacities equivalent to the fighting capacity of 300,000 U.S. troops is needed,” the Brussels-based Bruegel think tank estimates.

“Europe faces a choice: either increase troop numbers significantly by more than 300,000 to make up for the fragmented nature of national militaries, or find ways to rapidly enhance military coordination,” Bruegel said.

The question is how.

Making up the numbers

NATO is encouraging countries to build up personnel numbers, but the trans-Atlantic alliance isn’t telling them how to do it. Maintaining public support for the armed forces and for Ukraine is too important to risk by dictating choices.

“The way they go about it is intensely political, so we wouldn’t prescribe any way of changing this — whether to go for conscription, elective conscription, bigger reserves,” a senior NATO official said on the condition of anonymity because he wasn’t authorized to brief journalists unless he remained unnamed.

“We do stress the point that fighting with those regional plans means that we are in collective defense and likely in an attrition war that requires way more manpower than we currently have, or we designed our force models to deliver,” he added.

Eleven European countries have compulsory military service: Austria, Cyprus, Croatia, Denmark, Estonia, Finland, Greece, Latvia, Lithuania, Sweden, and non-European Union nation Norway. The length of service ranges from as little as two months in Croatia to 19 months in Norway.

Poland isn’t considering a return to universal military service, but rather a reserve system based on the model in Switzerland, where every man is obliged to serve in the armed forces or an alternative civilian service. Women can volunteer.

Belgium’s new defense minister plans to write a letter in November to around 120,000 citizens who are age 18 to try to persuade at least 500 of them to sign up for voluntary military service. Debate about the issue goes on in the U.K. and Germany.

Confronting the challenges

Germany’s professional armed forces had 181,174 active service personnel at the end of last year — slightly lower than in 2023, according to a parliamentary report released Tuesday. That means it’s no closer to reaching a Defense Ministry target of 203,000 by 2031.

Last year, 20,290 people started serving in the German military, or Bundeswehr, an 8% increase, the report said. But of the 18,810 who joined in 2023, more than a quarter — 5,100 or 27% of the total — left again, most at their own request during the six-month trial period.

The German parliament’s commissioner for the armed forces, Eva Högl, said that army life is a hard sell.

“The biggest problem is boredom,” Högl said. “If young people have nothing to do, if there isn’t enough equipment and there aren’t enough trainers, if the rooms aren’t reasonably clean and orderly, that deters people and it makes the Bundeswehr unattractive.”

At the other end of the scale, tiny Luxembourg has unique demographic challenges. Of its roughly 630,000 passport holders, only 315,000 are Luxembourgers. The number of people of military service age — 18 to 40 — is smaller still.

Around 1,000 people are enlisted. That’s small compared to some European powers, but bigger per capita than the U.K. armed forces. Recently, Luxembourg — where unemployment is low and salaries are high — has struggled to find just 200-300 military personnel.

Military service comes with many challenges too, not least convincing someone to sign up when they might be sent to the front, and hastily trained conscripts can’t replace a professional army. The draft also costs money. Extra staff, accommodation and trainers are needed throughout a conscript’s term.

Geir Moulson contributed to this report from Berlin.