The retire­ment of Justice Anthony Kennedy from the U.S. Supreme Court after the 2017 – 2018 court term and his replace­ment with Justice Brett Kavanaugh marked a poten­tial­ly piv­otal change in the con­sti­tu­tion of the Court with respect to death-penalty issues.

During Justice Kennedy’s thir­ty years on the Court, he became known as a swing vote, sid­ing with both the con­ser­v­a­tive and lib­er­al wings of the Court. His role as the Court’s swing vote extend­ed to death-penal­ty cas­es, in which he pro­vid­ed the deci­sive fifth vote against a chal­lenge to lethal-injec­tion prac­tices brought by Oklahoma death-row pris­on­ers in Glossip v. Gross, but authored a num­ber of key death-penal­ty deci­sions in favor of capital defendants.

Justice Kennedy was a lead­ing archi­tect of caselaw decid­ed under the Eighth Amendment’s evolv­ing stan­dards of decen­cy.” Under that doc­trine, the Court looked to var­i­ous mea­sures of con­tem­po­rary American val­ues to deter­mine whether a nation­al con­sen­sus had evolved against a penal prac­tice. His 5 – 4 deci­sions includ­ed Roper v. Simmons (2005), in which the jus­tices struck down the death penal­ty for juve­nile offend­ers under age 18, Kennedy v. Louisiana (2008), in which the jus­tices barred the death penal­ty for child rape and oth­er offens­es that did not result in death, Hall v. Florida (2014), strik­ing down Florida’s use of a strict IQ thresh­old in deter­min­ing whether defen­dants were intel­lec­tu­al­ly dis­abled and there­fore inel­i­gi­ble for the death penal­ty, and Panetti v. Quarterman, estab­lish­ing the rel­e­vance of a prisoner’s men­tal ill­ness in deter­min­ing whether he or she is men­tal­ly com­pe­tent to be executed.

In his opin­ion for the five-mem­ber major­i­ty in the Kennedy case, Justice Kennedy wrote: When the law pun­ish­es by death, it risks its own sud­den descent into bru­tal­i­ty, trans­gress­ing the con­sti­tu­tion­al com­mit­ment to decen­cy and restraint. For these rea­sons we have explained that cap­i­tal pun­ish­ment must be lim­it­ed to those offend­ers who com­mit a nar­row cat­e­go­ry of the most seri­ous crimes’ and whose extreme cul­pa­bil­i­ty makes them the most deserv­ing of execution.’” 

In Hall v. Florida , Justice Kennedy described the impor­tance of the Eighth Amendment, the risks of the death penal­ty, and the United States’ respon­si­bil­i­ty as a leader in the civilized world:

The Eighth Amendment’s pro­tec­tion of dig­ni­ty reflects the Nation we have been, the Nation we are, and the Nation we aspire to be. This is to affirm that the Nation’s con­stant, unyield­ing pur­pose must be to trans­mit the Constitution so that its pre­cepts and guar­an­tees retain their mean­ing and force.”

He con­clud­ed:

The death penal­ty is the gravest sen­tence our soci­ety may impose. Persons fac­ing that most severe sanc­tion must have a fair oppor­tu­ni­ty to show that the Constitution pro­hibits their exe­cu­tion. Florida’s law con­tra­venes our Nation’s com­mit­ment to dig­ni­ty and its duty to teach human decen­cy as the mark of a civ­i­lized world. The States are lab­o­ra­to­ries for exper­i­men­ta­tion, but those exper­i­ments may not deny the basic dig­ni­ty the Constitution protects.”