WASHINGTON — By prosecutors’ account, Jeffrey Sterling was a man with an ax to grind. Upset over losses in his legal squabbles with the CIA, they argued, the former officer leaked classified details to a reporter about an important program to learn about and deter Iran’s nuclear ambitions.

But the way his defense attorneys tell it, Sterling, 47, was a “patriot” who joined the CIA because he loved his country. They argued that he never told any unauthorized person about his clandestine work for the U.S. government, but he suggested that there were a few other people who might not have been so honest.

With those opening salvos, the two sides kicked off the criminal leak case against Sterling on Tuesday in federal court in Alexandria, Virginia, a years-in-the-making trial that promises to serve as a reminder of how aggressively the Obama administration has pursued alleged leakers.

Several witnesses, CIA employees, testified using only their first names and last initials, and were shielded by a screen that ran most of the width of the courtroom.

Jurors will have to decide whether Sterling gave classified material to New York Times reporter James Risen for his 2006 book “State of War” and whether that disclosure included secret national security information. At issue in particular is a chapter about an operation that was meant to sabotage Iran’s nuclear plans.

On Tuesday, Assistant U.S. Attorney James Trump said that reading the chapter in question was powerful evidence against Sterling. He said Risen’s view of the secret operation was incomplete and that the only person who had access to just the sphere of information that Risen reported was Sterling.

Trump argued that Risen had quoted Sterling in an unrelated article about Sterling’s discrimination lawsuit against the CIA and that the two men exchanged phone calls and emails. He said that when Sterling ultimately detailed concerns with the operation to the Senate Select Committee on Intelligence, his descriptions contained the “same spin” that would later appear in Risen’s book.

Trump said Sterling was “bitter, he was angry, he was seeking revenge.”