SANFORD, Fla. » From the very beginning, there was no more powerful theme in the fatal shooting of Trayvon Martin than the issue of race. But in the courtroom where George Zimmerman is on trial for second-degree murder, race lingers awkwardly on the sidelines, scarcely mentioned but impossible to ignore.

For African-Americans here and across the country, the killing of Martin, 17, black and unarmed, was resonant with a back story steeped in layers of American history and the abiding conviction that justice serves only some of the people.

Had Martin shot and killed Zimmerman under similar circumstances, black leaders say, the case would have barreled down a different path: Martin would have been quickly arrested by the Sanford Police Department and charged in the killing, without the benefit of the doubt.

Instead, there was no arrest for six weeks. And only after sharp criticism from civil rights leaders and demonstrations here and elsewhere did the Florida governor transfer the case to a special prosecutor from another county.

"For members of the African-American community, it’s a here-we-go-again moment," said JeffriAnne Wilder, an assistant professor of sociology at the University of North Florida. "We want to get away from these things, but this did not happen in a vacuum. It happened against the backdrop of all the other things that have happened before."

Yet inside a Seminole County courtroom, with the prosecution’s case against Zimmerman now over, race only occasionally punctuated the proceedings. The judge made it clear that statements about race would be sharply limited and the term "racial profiling" not allowed. What is more, overtly bringing up race might not have helped the prosecution.

"There is no question that race is the 800-pound gorilla in this trial," said Ed Shohat, a Miami lawyer who is also a member of the Miami-Dade County Community Relations Board. "But if you overplay that card either way, you lose with the jury. You have to let the jury come to its own conclusion."

For supporters of the Martin family, Martin’s death was part of a more complex tale of profiling and injustice. But this perception has run up against the protocols of a criminal trial and Florida’s expansive self-defense laws. These laws, critics say, give too much leeway to people who say they acted violently because they felt threatened.

Defense lawyers argue that Zimmerman, 29, a neighborhood watch volunteer in his gated community in Sanford, was attacked by a visiting Martin and, fearing for his life, shot him. Prosecutors counter that Zimmerman, whose mother is Peruvian, set out to confront Martin and initiated the fight that ended in Martin’s death. The charge is second-degree murder, inflicting death with spite, hatred or ill will. But no one in the courtroom is saying outright that race or racial hatred entered into the shooting.

"It’s like we are watching two different trials," said the Rev. Al Jackson, a pastor in Richmond Heights, a predominantly black community in Miami-Dade County, expressing frustration over the case and how it is unfolding at trial. "The law doesn’t care how this started, but we do. You are punishing this boy for defending himself, even though it wasn’t his fault."

Even so, race made an entrance on the first day of the trial. John Guy, a prosecutor, said in opening statements that Zimmerman had "profiled" Martin and pursued him because he was suspicious of the black teenager who looked as though "he was up to no good," as Zimmerman told the police dispatcher in a call that night. He cited Zimmerman’s apparent frustration in that call, quoting him making derogatory references to potential burglars who always seemed to "get away."

Race came up again when the jury heard four other phone calls to the police by Zimmerman reporting suspicious people in the neighborhood, all of them black. The fact that Zimmerman was studying criminal justice in college and seemed eager for a career in law or law enforcement rounded out the prosecution’s portrait of a would-be vigilante.

Race arose again, in topsy-turvy manner, when Rachel Jeantel, 19, a young black woman who was speaking to Martin on the phone shortly before he was shot, took the stand. Martin told her during that call, Jeantel said, that Zimmerman was following him; he called him a "creepy-ass cracker." The defense team quickly jumped on the words, suggesting to the jury that Martin had profiled Zimmerman.

In the cocoon of the courthouse, even Martin’s bullet-scarred hooded sweatshirt, positioned for jurors in a clear plastic frame, appeared less a poignant symbol for the thousands who marched in his name than a lamentable but necessary piece of evidence.

Still, black pastors, sociologists and community leaders said in interviews that they feared that Martin’s death would be a story of justice denied, an all-too common insult that to them places Trayvon Martin’s name next to those of Rodney King, Amadou Diallo and other black men who were abused, beaten or killed by police officers.

"Profiling, stereotyping, the disparity in treatment of African-Americans when it comes to criminal matters, how imbalanced it all is in the eyes of African-Americans," said the Rev. Lowman Oliver, the pastor at St. Paul Missionary Baptist Church in Sanford. "That’s why so many eyes are on this case. It’s nationwide and international."

The makeup of the jury, six women, none black, is occasionally noted. Race also framed Jeantel’s turn on the witness stand, which drew heckling online from white and black observers who mocked her demeanor. In testimony over two days, Jeantel, a high school senior and Martin’s friend, was clearly uneasy in the spotlight, at times impatient and often hard to hear or understand.

"She was mammyfied," said Wilder, the sociology professor, expressing disappointment over the reaction. "She has this riveting testimony, then she became, overnight, the teenage mammy: for not being smart and using these racial slurs and not being the best witness. A lot of people in the African-American community came out against her."

In the past two weeks, defense lawyers have methodically chipped away at the prosecution’s case, legal analysts said, raising the possibility of an acquittal. The law in Florida allows for the use of force if someone fears great bodily harm, and prosecutors must prove beyond a reasonable doubt that Zimmerman did not act in self-defense.

The twists and turns of the case – its weaknesses and legal complications – were not a factor for many supporters of the Martin family, until recently.

"We thought this was an open-and-shut case," said Jackson, the pastor in Richmond Heights.

Oliver, the Sanford pastor, said he remained optimistic. "You can feel a little sense that anger is re-emerging," he said.

The possibility of an acquittal has prompted community leaders, ministers and law enforcement officials in Miami and Sanford to begin preparing. This week in Miami, they will hold a meeting in Miami Gardens, where Martin lived, to talk about the complexity of the legal case and what has happened in the courtroom so far. They are also reaching out to young people in schools and parks and through websites, urging them to remain calm.

"It is important that we still maintain peace, even though decisions are not made to our liking," Jackson said. "That is our message, and that is what we are preaching."

Even the suggestion that trouble may follow an acquittal is fraught with racial overtones, particularly since much of the preparation is focused on the black community.

But in cities like Miami, which have experienced racial unrest, the ministers and activists said it was a reasonable concern. It is better to be prepared, they say, than caught off guard.

"Everybody wants to know the pulse of the community," Jackson said. "It’s not an insult to ask whether we feel there will be unrest."

As the trial begins its third and perhaps final week, there is widespread agreement that one fact rises above all others: post-racial America, as some hoped it would be after a black man was elected president, is still a work in progress.

"We are going to have to have a dialogue in this nation about racial matters," Oliver said.

© 2013 The New York Times Company