Was a Miramar retiree acting in self-defense or viciously overreacting when he shot and killed an off-duty federal agent at a Pembroke Pines post office?

That is what defense lawyers and prosecutors began to argue Tuesday before Broward Circuit Judge Bernard Bober in the case of James Wonder. Wonder, 69, is charged with manslaughter in the death of U.S. Customs and Border Protection agent Donald Pettit after a heated exchange of road rage.

Wonder faces up to 15 years in prison if convicted.

Wonder’s lawyers will argue in court in the coming days that Wonder should be immune from prosecution under Florida’s Stand Your Ground self-defense law.

According to police reports, Wonder and Pettit, who was 52, got into a shouting and finger-pointing match while driving on Pines Boulevard near Dykes Road on the morning of Aug. 5, 2008. Wonder pulled into a post office parking lot, and Pettit followed.

Pettit, who worked as a polygrapher, got out of his car to confront Wonder, who shot the agent once in the head.

“Mr. Wonder was reasonably acting in self-defense,” defense lawyer Frank Maister said in court Tuesday.

Prosecutor Michelle Boutros said that claiming self-defense is about more than just if Wonder said he was felt he was in danger.

“It’s what a reasonable person would believe,” Boutros said.

Wonder’s self-defense claim rests on Florida’s Stand Your Ground law, which states that individuals who are following the law have no duty to retreat in the face of a threat, and that those individuals may meet force with force if they believe it is necessary to protect themselves or another, or to prevent a forcible felony.

Testimony is scheduled to begin again on Thursday.