The man with the gun usually has the advantage.

But not in this case — not when a 20-year-old thief tries to rob someone with more than 20 years of military experience.

Army veteran Robert Tillman, 46, had gone to a Kansas City car wash Sunday morning to clean his girlfriend’s Pontiac sport utility vehicle. A gunman slipped into his car wash bay at 3011 Van Brunt Blvd. and accosted him when he returned from the change machine.

“You know what time it is,” the gunman barked. “Give it up!”

Tillman couldn’t believe it. “Are you kidding me?” he asked.

“Yeah,” the robber replied. “Give me your money. Give me everything. Empty your pockets!”

Tillman’s next statement could have been a clue to the robber that he had targeted the wrong victim.

“Sir,” Tillman said, using military courtesy, “I don’t have any money. I have a single dollar bill and $6 in change.”

Enraged, the robber demanded more.

“I know you got more! Don’t make me shoot you!” he shouted as he chambered a round in his handgun.

Tillman showed his empty pockets.

So the robber asked for Tillman’s keys.

“No,” Tillman said. “I won’t.”

The robber repeated his demand and Tillman repeated his refusal.

Tillman worried the gunman would shoot him whether he gave his keys or not. The gunman might even try to drive him away from the scene and kill him elsewhere, Tillman thought.

He decided he was going to “go for it.”

“What’s the difference?” Tillman thought. “If he’s going to shoot me, at least I’ll have some witnesses here.”

Tillman stepped closer to the gunman and reached out, as if he were going to hand over the keys.

“Hey, man! Watch out!” Tillman yelled. “Someone’s behind you!”

As the robber turned, Tillman jumped at him and grabbed the arm with the gun. They tussled. Tillman slammed the gunman to the ground, using hand-to-hand combat techniques from the military.

The gun fired a single stray round and clattered onto the pavement. Tillman kicked it away and forced the gunman into a choke hold.

Tillman locked up the robber’s left arm with one arm. Tillman wrapped his other arm around the robber’s throat as the robber laid facedown on the ground.

Each time the robber tried to break free, Tillman squeezed his arm a little tighter around the robber’s neck.

“He had to decide whether he wanted to breathe or not,” Tillman said.

Tillman asked another car wash patron to call 911 and grab the gun so the robber couldn’t reach it.

Meanwhile, the robber begged for sympathy.

“I’m sorry,” he said. “I thought you were someone else.”

“What?” Tillman asked incredulously. “You mean you were going to steal from someone else?”

Tillman considered that there was some truth in the robber’s statement. He probably was looking to rob someone else — someone who wouldn’t fight back.

“But I have two kids,” the robber said.

“I have kids, too,” Tillman said, “But you don’t see me out here stealing.”

Police arrived and arrested Dominic M. Anderson, 20. On Monday, Jackson County prosecutors charged him with attempted robbery and armed criminal action. He remained in jail in lieu of a $150,000 bond.

Tillman said fighting back might not be the right choice for everyone, but he believes it was right for him. He’s seen people shot, mangled and burned in his overseas deployments. He’s arrested and guarded prisoners of war in camps in the desert.

“I didn’t show any fear,” Tillman said. “He didn’t know how to react to that.”