Ms. Biloshitska is one of thousands of Ukrainian civilians who have signed up to learn combat skills in training programs created and run by the government and private paramilitary groups. The programs are part of the country’s strategic defense plan in the event of a potential invasion by Russia — to foster a civilian resistance that can carry on the fight if the Ukrainian military is overwhelmed…

Ukraine has drawn a lesson from the United States’ wars in Iraq and Afghanistan of the past two decades, when guerrillas provided enduring resistance in the face of vastly superior American firepower.

“We have a strong army, but not strong enough to defend against Russia,” said Marta Yuzkiv, a doctor working in clinical research, who signed up for training this month. “If we are occupied, and I hope that doesn’t happen, we will become the national resistance.”

Government-sponsored training for civilians has underpinned Nordic and Swiss military strategies for decades, and is gaining traction as a military doctrine in Eastern Europe.