Earlier this week, White House spokesman Jay Carney said of the Trayvon Martin case, “obviously we’re not going to wade into a local law enforcement matter.” But this isn’t local anymore. This is a national story, an outrage that has galvanized people around the country. This morning, Obama finally spoke about the Martin tragedy, saying, “If I had a son, he’d look like Trayvon.”

View Photo Gallery: The fatal shooting of Florida teen, an unarmed black 17-year-old, by a neighborhood watch volunteer in Sanford, Fla., has led to a federal investigation, numerous rallies and a national spotlight.

We live in a national village now. Although there may be political perils for the president in taking on so racially charged a case — gosh, Florida’s a swing state! — he’s paid a salary to do the heavy lifting. This is a shocking story. Notwithstanding the Skip Gates/beer-summit fiasco, Obama’s actually had some of his best moments when he had to handle controversial, emotionally raw issues. Think of his Rev. Wright “race” speech in Philadelphia. He memorably offered soothing words after the Tuscon massacre and the subsequent eruption of ideological rancor. This story isn’t going away, because the details are so powerful and tragic and have outraged so many Americans. See Gene Robinson’s excellent column this morning.

Obama’s decision to address the case corrects the impression that the White House doesn’t want the president taking on racial issues. Maybe someone at the White House read the Post this morning and saw this passage about Eric Holder:

“On policy issues and issues that involve race, Eric Holder is now, during this campaign context, the official black guy of the Obama administration,” said the Rev. Eugene F. Rivers III, senior policy adviser to the Church of God in Christ, one of the largest black denominations in the country. “Because the president cannot in any way, directly or indirectly, be associated with anything that whispers race, and for perfectly logical reasons.”

Well, this story isn’t going away. The Trayvon Martin case has the potential to become an ongoing national story with massive media attention. That, in turn, means it could become the source of a lot of divisiveness, as did the O.J. trial almost two decades ago (note that Geraldo, who got a huge career boost out of covering O.J. every night, weighed in with some unhelpful remarks this morning about why George Zimmerman shot Martin).

The fatal encounter between Martin and Zimmerman brings to mind (for this old reporter) the Nevell Johnson/Luis Alvarez case back in Miami’s Overtown neighborhood in 1982. Johnson was black, Alvarez Hispanic. Johnson was playing an arcade game when Alvarez, a young, inexperienced cop, came in with his partner and saw that Johnson had a gun tucked in the back of his waistband. Alvarez put his service weapon to Johnson’s head. What happened next was the subject of Alvarez’s trial, but the bottom line is that Johnson turned toward Alvarez and Alvarez’s gun went off and Johnson was killed.

The shooting incited three days of rioting. This was, for many blacks in Miami, an obvious replay of what had happened to Arthur McDuffie, a black insurance executive who, during a traffic stop, was beaten to death by four white police officers. When the officers were acquitted, Miami’s Liberty City erupted in riots. The Alvarez-Johnson case played out the same way. Alvarez pled self-defense. The jury acquitted him and there was another eruption of street violence.

Situations like this rarely end neatly and with everyone agreeing that justice has been served. It’s a fitting topic for someone who is a national leader and isn’t just a “local law enforcement matter.”