Washington ? Urging Americans to “do some soul searching,” President Barack Obama injected himself into the emotional debate over the fatal shooting of a teenager in Florida, turning the racially charged case into a personal matter for the nation’s first black president.

“If I had a son, he’d look like Trayvon,” Obama said Friday.

Obama’s words also catapulted the death in Florida of 17-year-old Trayvon Martin, already the focus of major national attention, into the presidential campaign. Three Republicans seeking Obama’s job all used the word “tragedy” to describe the shooting, as the president did.

“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 at the White House.

Obama said the parents of Martin, who was shot on Feb. 26 in Sanford, Fla., a suburb of Orlando, have a right to expect “that we’re going to get to the bottom of exactly what happened.”

Martin was shot by neighborhood watch volunteer George Zimmerman, who said he was acting in self-defense. Zimmerman’s father is white, and his mother is Hispanic. The shooting has stoked debate over race as well as other issues. Obama did not mention Zimmerman in his comments.

Republican presidential candidates quickly weighed in after Obama spoke.

Former Pennsylvania Sen. Rick Santorum called the shooting a “horrible case.” Referring to Florida’s “stand your ground” law, which gives people wide latitude to use deadly force rather than retreat during a fight, Santorum said: “Stand your ground is not doing what this man did.”

Former Massachusetts Gov. Mitt Romney, campaigning in Louisiana, said the shooting was a “terrible tragedy, unnecessary, uncalled for, and inexplicable at this point.”

Romney said it was “entirely appropriate for the district attorney to be looking into this and to have called a grand jury and to find out what the facts are. We hope that justice is done in this case.”

Former House Speaker Newt Gingrich of Georgia also called it a tragedy and credited local authorities for empaneling a grand jury.

“There’s a point in there where there ought to be some kind of signal that’s pretty clear that this is a guy who’d found a hobby that’s very dangerous,” Gingrich said of Zimmerman.

Florida is a large and diverse state that plays an influential role in presidential elections — it was a deciding factor in the 2000 election following a lengthy recount. The Orlando area in central Florida is particularly important, acting as a bellwether for statewide elections.

The case resonates with many black Americans, a key voting group during Obama’s 2008 election, who see it as an example of bias toward blacks. Civil rights groups have held rallies in Florida and New York, saying the shooting was unjustified. Of Sanford’s 53,000 residents, 57 percent are white and 30 percent are black.