In what circumstances have courts upheld mandatory sentences of life in prison without possibility of parole for a single conviction of possession of cocaine?

In Harmelin v. Michigan (1991) 501 U.S. 957, 111 S.Ct. 2680, 115 L.Ed.2d 836 the United States Supreme Court upheld a mandatory sentence of life in prison without possibility of parole for a single conviction of possession of cocaine. In Rummel v. Estelle (1980) 445 U.S. 263, 100 S.Ct. 1133, 63 L.Ed.2d 382 the court upheld a life sentence for a recidivist convicted of a series of nonviolent financial offenses. In light of the court's determination that these sentences were not cruel and unusual, defendant's sentence for multiple counts of attempted sexual offenses against minors, after prior convictions for eight felony counts of similar completed offenses, is not cruel and unusual under the federal constitutional standard.