One of the go-to arguments of gun control advocates who try to portray our Second Amendment as an outdated anachronism is that armed citizens just wouldn’t stand a chance against the might of a modern military force bristling with tanks, missiles, and even nuclear weapons (looking at you, Eric Swalwell).

The armed citizens of Ukraine, however, are helping to put that argument to rest. So far the nation has defied expectations and has continued to to resist the Russian invasion, repelling many of the attacks against the country’s biggest cities, and the country’s Territorial Defense Force, which includes many individuals who were simply private citizens a couple of weeks ago, is having an impact, according to Ukrainian officials.

“In the city itself, the territorial defense detachments are working quite effectively,” Mykhailo Podolyak, an adviser to the Ukrainian presidential chief of staff, said in a statement Saturday morning. “It turned out that people are coming out, defending their homes. It wasn’t expected by analysts of the Russian General Staff.”

I don’t think it was expected even for some of those who’ve shown up to volunteer, many of whom may never have thought about defending their country with a gun until last week but who are now heading down to their nearest recruitment center.

Men from their 20s to late 50s, from a range of backgrounds, showed up. Igor, 37, an economist for an online retailing company, who didn’t want his last name published for safety reasons, stood in line for his gun. He spoke at barely a whisper and his lips trembled. The dull thud of bombs or artillery could be heard in the distance.

“I never served in the army or with the police or anything,” he said. He said he hoped to be able to figure it out. He was worried, he said. “But people who are really afraid are sitting at home. They aren’t out here now.”

“Everybody in our country needs to defend — women, girls, everybody,” said Denis Matash, 33, the manager of Milk, a Kyiv nightclub, standing in line with about 50 other men at the recruitment center. “I don’t think they understand where they came,” he said of the Russians. “Look at what is happening here.”

Grigory Mamchur, 40, who works as a male strip dancer at the Milk nightclub, part of the now shuttered but once booming nightlife scene in Kyiv, was also in line for a Kalashnikov.

“There wasn’t even anything to think about,” Mr. Mamchur said. “We will defend the country however we can. This could be our last chance.”

The Territorial Defense Force and the private citizens who are taking up arms against their country’s invaders can’t thwart the Russian military on their own, but they can and have made life hell for Russian troops. In addition, the massive mobilization of civilian volunteers serves as a psychological boost for Ukrainians and is helping to obliterate the argument made by Vladimir Putin that the Ukrainian campaign is about “liberating” a grateful populace from their democratically-elected overlords.

The popular resistance raises a real prospect for Moscow of a protracted nationwide war against counterinsurgent fighters that could drain Russian resources, embarrass the Kremlin and make its leaders even greater international pariahs as civilian deaths mount.

Ukrainian and Western officials say the Russian assault on the capital aims to kill or capture the country’s leaders and install a puppet government. But they also say Mr. Putin has misjudged the will and ability of Ukraine’s army and citizens to fight.

At Polish border posts in the country’s southeast, a steady stream of Ukrainians who have been living in Poland have crossed over on foot and in cars, answering calls on social media to join the fight.

“Every truck company in Europe has Ukrainian drivers, and we are organizing ourselves to go,” said Vitalis Kos, a 38-year-old trucker, waiting to drive across the border. The car behind him, and another in front, were also carrying men to the front.

“We’re not going to let him turn our country into Syria,” said Mr. Kos.

And those Ukrainians will soon be getting reinforcements from citizens of other nations, with the establishment of an international legion that has already drawn the interest of some American special forces veterans.

A group of 10 special operations forces veterans are staging in Poland and preparing to cross into Ukraine, where they plan to take up President Volodymyr Zelensky on his offer to “join the defense of Ukraine, Europe, and the world,” according to a US Army veteran arranging their passage.

The group, composed of six US citizens, three Brits, and a German, are NATO-trained and experienced in close combat and counterterrorism. They want to be among the first to officially join the new International Legion of the Territorial Defense of Ukraine that Zelensky announced Sunday, according to text messages reviewed by BuzzFeed News. Two former American infantry officers are also making plans to come to Ukraine to provide “leadership” for the group, the Army veteran recruiter said.

Ukraine’s armed citizens aren’t just serving as a check on the Russian army’s advances, they’re an inspiration to others at home and abroad, drawing in volunteers that might otherwise have sat out the conflict instead of coming to the country’s defense.

Ukraine’s military has been brilliantly effective, and I believe the mass mobilization of the general public into a self-defense force has played a major role in keeping the country in the fight. No, armed citizens can’t go toe-to-toe against a cruise missile, but if Putin wants to occupy Ukraine and not merely destroy it, then he’s going to need boots on the ground. As long as the soldiers wearing those boots are meeting resistance from average Ukrainians armed with everything from AK-47s to Molotov cocktails, subjugating that nation is going to be an impossible task.