The family of 2013 Boston Marathon bombing victim Martin Richard, from left, mother Denise, brother Henry, and father Bill Richard, place their hands over their hearts as they stand with former Boston Mayor Tom Menino, right, during a tribute in honor of the one year anniversary of the Boston Marathon bombings, Tuesday, April 15, 2014 in Boston. (Charles Krupa/AP)

NO ONE understands more keenly than Bill and Denise Richard the monstrous cruelty of Dzhokhar Tsarnaev in setting bombs near the finish line of the Boston Marathon. Their eight-year-old son was killed, their 7-year-old daughter lost a leg and both parents were wounded, all in full view of another son who has had to live with the horror of that day. But with the penalty phase of Mr. Tsarnaev’s trial about to begin, the Richards have made an extraordinary appeal to federal prosecutors to take the death penalty off the table. The deeply personal request adds a new dimension to this highly charged issue and should give pause to those who think justice for Mr. Tsarnaev cannot be served by a life sentence.

“We know that the government has its reasons for seeking the death penalty, but the continued pursuit of that punishment could bring years of appeals and prolong reliving the most painful day of our lives,” the Richards wrote in a letter that appeared Friday on the front page of the Boston Globe. That process could cause their surviving children to go through what the family has suffered over and over again. The Richards propose that the government drop its bid for execution in exchange for Mr. Tsarnaev spending the rest of his life in prison with no possibility of release and waiving his right to appeal.

The Richards’ appeal, subsequently seconded by a married couple who lost limbs in the 2013 attack, comes as the jury that convicted Mr. Tsarnaev reconvenes Tuesday for his sentencing. In contrast to the first phase of the trial, when defense attorneys did not contest Mr. Tsarnaev’s guilt in the bombing that killed three people and injured 264, the coming weeks are sure to feature impassioned testimony. The government must prove there was at least one aggravating factor that qualifies the crimes for the death penalty while the defense will argue for factors that mitigate against execution. In effect, the jury will be balancing the heinous and calculated nature of the crime — which includes the murder of young Martin Richard — against Mr. Tsarnaev’s young age, lack of a criminal record and claim that he was controlled by his older brother, now dead, who was the mastermind of the attack. A vote for the death penalty must be unanimous

The Richards can speak only for themselves; indeed there are victims and their family members who want Mr. Tsarnaev to be put to death. But no matter the outcome for Mr. Tsarnaev, the Richards are right that “what was taken from us” can never be replaced. That makes all the more poignant their resolve “to get up every morning and fight another day” and all the more powerful their argument that “as long as the defendant is in the spotlight, we have no choice but to live a story told on his terms, not ours.”