Does the first African American president have a duty to weigh in on the senseless killing that has stirred the fears that so many black parents feel when they send their sons out the front door every day?

The White House has declined to provide any details as to President Obama’s thoughts about the Trayvon Martin killing — and that is smart. One person who says so, via Twitter, is none other than John Dean, best known as White House counsel in the Nixon White House.

Dean recalled an episode involving his old boss and one of the most infamous crimes in American history — one that should serve as a cautionary example to any president who is tempted to vent his own outrage at the senseless and heinous acts of which human beings are capable.

On Aug. 3, 1970, amid the national outrage during the trial of Charles Manson, Nixon opined to reporters in Denver that the saturation coverage had had the unintended effect of making Manson “rather a glamorous figure” for having led a cult that murdered actress Sharon Tate and seven others.

Nixon added: “Here is a man who was guilty, directly or indirectly of eight murders without reason.”

The president’s comments caused a sensation.

Nixon’s press secretary, Ronald L. Ziegler, tried to rectify the president’s comments, handing reporters a statement in which Nixon said: “I do not know and did not intend to speculate whether the Tate defendants are guilty, in fact, or not. All of the facts in the case have not yet been presented. The defendants should be presumed to be innocent at this stage of their trial.”

The next day, Manson stood up in court and held up that day’s blaring Los Angeles Times headline: MANSON GUILTY, NIXON DECLARES. The judge in the case polled the jurors and one said: “If the president did say that, it was pretty stupid of him.”

Of course, Obama has some personal experience in this regard, having felt a backlash from his declaration that Cambridge police had “acted stupidly” in their arrest of Harvard scholar Henry Louis Gates Jr. in 2009.

But there are times when the public is perfectly capable of sorting out its own feelings without being led from the bully pulpit. This is one of them.