Belgium would be the first country in modern Western military history to make such a move, according to experts from the European Defense Agency, which monitors defense capabilities of European Union member states.

“Every army trains to go to war, and there will be no sleeping at home when you go to war,” said Vir Maram, 35, a reservist corporal of the French Foreign Legion who served several tours under the command of Western armies and NATO in Afghanistan, Iraq and Mali and who is studying international security in Brussels.

“An army evolves with the way that it fights,” he added, “but the only thing that changes are the weapons we fight with — the nature of war itself doesn’t change, and so the basic principles of the army don’t change.”

Military service was mandatory in Belgium until 1994 for men turning 18 or ending their studies for one year. Since then, the head count of the country’s armed forces has gradually diminished, to about 28,500 active personnel from 40,000.

Belgium now has about 2.6 soldiers per 1,000 civilians, fewer than many of its NATO allies. And the average age has crept up.

“It’s almost like a Dad’s Army,” said Roger Housen, a retired colonel in the Belgian armed forces, referring to a television comedy about the British Home Guard, a World War II volunteer force made up of men exempt from conscription, often because they were considered too old to fight.

“The army is right to try to attract more youngsters, as many senior personnel will retire over the next five years,” Colonel Housen said. But the requirement to live in barracks, he said, was not the main factor driving young people away.