WASHINGTON » President Barack Obama did not mention race even as he addressed it Friday, instead letting his person and his words say it all: "If I had a son, he’d look like Trayvon."

Weighing in for the first time on the death of Trayvon Martin, the unarmed black teenager shot and killed a month ago in Florida by a neighborhood watchman, Obama in powerfully personal terms deplored the "tragedy" and, as a parent, expressed sympathy for the boy’s mother and father.

"I can only imagine what these parents are going through. And when I think about this boy, I think about my own kids," Obama said. "Every parent in America," he added, "should be able to understand why it is absolutely imperative that we investigate every aspect of this and that everybody pulls together — federal, state and local — to figure out exactly how this tragedy happened."

While speaking movingly from his perspective as the father of two girls, one a teenager, Obama notably made no reference to the racial context that has made the killing of Trayvon and the gunman’s claim of self-defense a rallying point for blacks. Since Obama first began campaigning to be "president of all the people," as his advisers would put it when pressed on racial issues, he has been generally reluctant to talk about race.

And after his historic election as the first black president, Obama learned the hard way about the pitfalls of the chief executive opining on law enforcement matters involving civil rights.

His remark at a news conference in the summer of 2009 that a white police officer in Cambridge, Mass., had acted "stupidly" in arresting a black Harvard law professor, Henry Louis Gates Jr., at his home led to a national controversy that ended with Obama holding a peacemaking "beer summit" with the two men at the White House.

Until Friday, Obama had refrained from commenting on the death of Martin, 17, a high school student who was killed on the night of Feb. 26 in Sanford, Fla., near Orlando. George Zimmerman, 28, the neighborhood watch volunteer, said he fired at Martin in self-defense, although there is no apparent evidence that the teenager, who held only a bag of Skittles candy and iced tea, was doing anything wrong.

But when a reporter asked about the case at a White House event introducing Jim Yong Kim as his choice to be president of the World Bank, Obama, who typically leaves such events ignoring the shouted questions of reporters, seemed prepared.

"It was inevitable given the high-profile nature of this story that he would be asked about it," his press secretary, Jay Carney, said later. He added that Obama "had thought about it and was prepared to answer that question when he got it."

Carney himself had refused for days to speak for Obama about Martin’s death, and other advisers Friday likewise declined to weigh in on the thinking at the White House about the case and its repercussions. Obama’s mostly white male inner circle has long been reluctant to talk for their boss when the subject is race, given how personal it is for him. One aide, speaking only on the grounds of anonymity, said that there was no internal debate about how to respond to Martin’s death, but that Obama wanted to await the Justice Department’s initial review of the case and the announcement this week by his attorney general, Eric H. Holder Jr., that the civil rights division would investigate.

In his remarks, Obama endorsed the Justice Department investigation as well as efforts by local and state agencies in Florida to examine the circumstances of the shooting. Martin’s parents "are right to expect that all of us as Americans are going to take this with the seriousness it deserves, and that we’re going to get to the bottom of exactly what happened," Obama said.

The president indicated his caution in not reacting earlier was due to the hazards of addressing an issue under inquiry.

"I’m the head of the executive branch and the attorney general reports to me so I’ve got to be careful about my statements to make sure that we’re not impairing any investigation that’s taking place right now," he said.

The Rev. Al Sharpton, the civil rights leader who organized a rally Thursday night in Florida protesting the handling of the case and has been working with the Martin family, praised Obama’s comments and took issue with black critics who say he should have spoken out sooner.

"We’re trying to win a case, not just have the president make high-profile statements," Sharpton said in an interview. "As one who’s been with the family, the president making a statement before the Justice Department announced an investigation could have been used by Zimmerman to say the White House was pre-judging a legal case."

Charles J. Ogletree, a black law professor at Harvard who taught Obama there and remains a confidant, said there was no doubt the president had been moved by Martin’s death.

"Nothing is more frightening for a parent than losing a child," Ogletree said. "I know personally that he felt this pain, from the moment he was made aware of the case." He added: "He has two young daughters. This is personal."

Carney said he could not say whether Obama planned to call Martin’s parents, as some black activists have urged. Boyce D. Watkins, a Syracuse University professor and the founder of the Your Black World coalition, said Friday in a Twitter message, "If Trayvon’s mother were white, would Obama give her a call?"

Watkins, in an interview, called Obama’s statement "a step in the right direction," but added that the president could "squash a great deal of the criticism" with a call to the parents. And while applauding Obama’s comment that his own son would look like Martin, Watkins said the president’s remarks were characteristic of how Obama talks to black people.

"That’s what I would refer to as a standard political smoke signal that President Obama sends through the back door to the black community," Watkins said. "He communicates to the black community in code language. That’s a subtle way of saying, ‘I know this kid is black."’

Obama’s comments appeared to prompt several of the Republicans campaigning to run against him to weigh in against the shooting for the first time. Both Newt Gingrich and Rick Santorum said that based on what they knew, Florida’s "Stand Your Ground" self-defense law should not apply in Zimmerman’s case.

Speaking publicly for the first time Friday evening, Craig A. Sonner, Zimmerman’s lawyer, said on CNN that he would not use the Stand Your Ground defense should his client be charged in the shooting. He said he would use self-defense.

Santorum, campaigning at a shooting range in Louisiana, which holds a presidential primary Saturday, called the decision of local officials not to immediately prosecute Zimmerman "another chilling example of horrible decisions made by people in this process." Mitt Romney, the Republican front-runner, told reporters in Louisiana that the shooting was "a terrible tragedy, unnecessary, uncalled for and inexplicable at this point."

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