Gao pulled the device from his armband and tapped the screen a few times. Lights came up and the situation below was illuminated. A dozen mannequins were placed here and there. Some hiding, others out in the open. A human employee stood in the middle of it. “A standard hostage situation,” Han said. “Eight terrorists, seven hostages.”

The front door to the building was smashed down by a small battering ram machine on tracks. It pushed its way inside, taking fire from several of the armed terrorist mannequins. Sparks flew as bullets hit the armor plating.

“Live ammo?” Kurt said.

“Of course,” Han said. “Limited powder, at this point. We don’t want ricochets killing anyone.”

“What about your employee down there?” Kurt asked. “How do the machines know not to shoot him?”

“He’s wearing an identifier around his neck,” Han said. “It tells the robots not to shoot him. Similar tools can be used on joint human and robotic assaults. Use of robotics will reduce friendly fire deaths by ninety-five percent.”

“Impressive,” Kurt said.

Down below, other machines with weapons pushed in behind the battering ram robot. Instead of wheels, they had six legs and they clambered up and over every obstacle with ease. They rapidly targeted and silenced the first wave of terrorists and pushed deeper into the building.

“They find their targets using a combination of heat sensors, sound waves and cameras,” Han said. “They communicate with one another as well. What one of them knows, all of them know.”

The advancing machines paused, scanned the thermal output through the walls of the next room and broke into it. A quick gunfight ended moments later.

“And, just like that,” Han said, “the terrorists are dead and the hostages are rescued. Not one of them has been hit.”

Kurt was impressed. “How do the machines differentiate between terrorists and hostages?”

“We call it a discriminator function,” Han said. “A combination of facial recognition patterns conforming to the known captives, heat sensors and a weapon recognition program that allows the processor to determine which humans are holding guns and which aren’t.”

“Ingenious.”

“And the ones that are damaged can be repaired or replaced. No one has to cry over a ruined machine.”

A terminal beside them printed out a battle report. Han interpreted it. “Twenty-one shell hits on various robots. Two machines sustained minor damage. A comparable effort using human policemen or soldiers would have resulted in the death of several personnel and at least half the hostages. The facts are unassailable.”

“Unlike the terrorist stronghold,” Kurt joked.

“Warbots like these will spare soldiers the most dangerous tasks in the field,” Han said.

“Warbots?”

“A catchy name, is it not?”

“But this is a police demonstration,” Kurt pointed out.

“Yes,” Han said, “but ultimately

armies of machines will take the fight to the world’s most dangerous areas. They’re more rugged, more lethal and more dependable. They can fight twenty-four hours a day, seven days a week, without the need for sleep, food or medical attention. They will reduce human death and collateral damage, eliminate decades of post-combat suffering by wounded and traumatized soldiers and their families.”

“They will cause death on the other side, of course.”

“Not true,” Han said. “Not only are robots more accurate, thus limiting collateral damage, they are more humane. A robot has no feelings. It won’t take revenge on captives that might have destroyed its comrades. It won’t lose its mind at the horror of war and start killing indiscriminately. A robot will not rape or torture its captives nor steal or plunder.”

Kurt nodded. He’d heard the arguments on both sides. Some were afraid that robotic soldiers would go out of control. Others pointed out that human soldiers were prone to emotion and strain and subject to losing control themselves. Like most things, no one would know the truth until it arrived.

They moved on, coming to an overlook. On the floor down below, a slew of machines were building a section of highway. One machine used a jackhammer to break up concrete. Another machine scooped it up and lifted it into a driverless truck, which, making a tight three-point turn without hitting anything, then hauled it away, disappearing through a door at the far end of the convention hall.

“While robotic armies might be decades off,” Han began, “self-driving vehicles are right around the corner.”

“We have them already,” Kurt said.

“A few,” Han admitted. “But the next wave goes far beyond what exists today. CNR has even developed a driverless race car. It will compete with the greatest racers in the world and outclass them with ease.”