Hello, I’m Zhan Qingyun.

After the United States restored the death penalty in 1976, twenty-two people were sentenced to death for crimes committed as minors. In 2005, Roper v. Simmons held juvenile executions unconstitutional.

The case was highly controversial. Serious juvenile crime drew public concern, and most death-penalty states had not exempted minors.

In Stanford v. Kentucky, the Supreme Court had barred execution below sixteen while implicitly permitting it from sixteen to eighteen.

Roper drew a categorical line: anyone under eighteen, even by one day, could not be executed.

The underlying crime had attracted great attention.

In 1993, seventeen-year-old Christopher Simmons and two younger friends planned to rob and murder Shirley Crook. One withdrew and became a key witness. Simmons and Benjamin entered Crook’s home, bound and blindfolded her, drove her to a state park, and threw her from a bridge to her death.

Evidence was overwhelming. Simmons confessed and reenacted the crime on video, while the withdrawing accomplice described the plan. This was premeditated murder, not accident or manslaughter.

A jury convicted Simmons of first-degree murder and recommended death; the trial court agreed, and repeated appeals affirmed.

Then the law changed. In Atkins v. Virginia (2002), the Supreme Court held execution of intellectually disabled people unconstitutional. Simmons used that opening to reach the Court.

In 2005, the Supreme Court held that executing anyone under eighteen violated the Eighth Amendment.

The Eighth Amendment prohibits cruel and unusual punishment, adjectives leaving wide interpretive room. Is executing a sixteen-year-old cruel, an eighteen-year-old cruel, but a nineteen-year-old not? The boundary is humanly drawn.

Justice Anthony Kennedy—the familiar swing vote in many 5–4 cases—wrote the opinion, as he had the key Atkins decision. His defense drew intense dispute.

Kennedy offered three main arguments. First, social-science research showed adolescents less mature and responsible and disproportionately involved in irrational conduct.

Society uses eighteen as a major boundary: younger people cannot serve on juries, marry, or vote. If they lack maturity for essential civic rights, they deserve corresponding protection.