So he was stunned when he got the call about the attack.

Surveillance video shows Mr. Rodriguez and the retired Marine take a corner table where his back could be against the wall — typical behavior of veterans with PTSD.

After several minutes of not ordering, he said loudly that he had to get out of the restaurant, witnesses told the police. He tried to go through a side door but found it locked, so he stood, wringing his hands. He cursed about Iraq. Then suddenly, he picked up a chair and hurled it at a waiter.

Police reports say the waiter had a sore shoulder but no visible marks. The waiter declined to comment. Mr. Sahib, who has not spoken to Mr. Rodriguez, said the attack brought back dark memories from the war, and made his family fear more violence. “We always feel love for this city,” he said. “But now we are afraid to keep our door open.”

Mr. Rodriguez has offered to apologize, but so far the family has been hesitant. “He has caused such harm,” said Tiffany Sahib, Mr. Sahib’s wife.

Mr. Rodriguez acknowledged in an interview that he has never been able to completely control the effects of his combat experiences, but said he did not know what caused him to hit the waiter. It is a blank. “All I can remember, honestly, is being handcuffed by the police,” he said.

After his arrest, the Marine Corps forced him to retire. Freed from the pressures of his career, he entered an intensive program for substance abuse and PTSD. In the months since, he has tried to make peace with the fact that his dedication to his career was also its undoing.

But Mr. Rodriguez says he is disheartened that the final assessment of years of service could be conviction for a hate crime.

“I’m sorry about what happened,” he said. “But no one tries to understand what we went through.”