Dufour v. State, 69 So. 3d 235

Dufour was convicted of the 1982 Miller murder and sentenced to death; direct appeal upheld the conviction and death sentence.
Postconviction proceedings began in 1992 with Rule 3.850 and later Rule 3.203/3.851; Dufour sought a mental retardation determination to bar execution under Atkins.
Two sides presented competing neuropsychological evaluations; the scores ranged from IQs in the low 60s–70s and raised questions about validity and malingering.
The circuit court held Dufour did not prove mental retardation under the three-prong test (intellectual functioning, adaptive behavior, onset before 18) and noted potential testing irregularities.
The court concluded there was competent, substantial evidence supporting no adaptive deficits and that even with IQ concerns, the adaptations argued by Dufour did not establish MR; the SEM application issue could affect the IQ prong.
The Florida Supreme Court affirmed, holding that Dufour failed to establish mental retardation; it declined to decide constitutional challenges to the MR standard, and noted evidentiary issues but found harmlessness in most challenged items.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Dufour proved significantly subaverage intellectual functioning	Dufour's scores (IQ ≤70) meet prong one under 3.203/921.137	Court should require IQ ≤70 with proper SEM handling and consider all scores	Not proven under the three-prong test; majority rejects while acknowledging SEM error but not dispositive for MR
Whether Dufour showed deficits in adaptive behavior concurrent with subaverage IQ	Deficits existed in adaptive functioning	Adaptive deficits not established; alternative explanations plausible	Affirmed that adaptive behavior deficits were not proven to a level required by the statute
Whether the pre-18 manifestation element was satisfied	Evidence suggested early-life risk factors; MR could be shown	Court need not decide if pre-18 manifestation was proven given other prongs unmet	Not reached as MR not established on other prongs; Court did not address this prong finality here
Whether the clear-and-convincing standard for adaptive behavior violates due process	Standard is unconstitutional post-Atkins/Cooper	Standard appropriate for MR inquiries	Constitutional challenge not reached; court relied on lower standard as dispositive
Whether evidentiary rulings and admission of certain documents affected the MR determination	Challenged documents and projector disclosure tainted the experts	Any error was harmless given disposition on MR elements	Harmless error; no reasonable possibility that challenged evidence affected the MR ruling

Atkins v. Virginia, 536 U.S. 304 (U.S. 2002) (execution of the mentally retarded prohibited; states must implement MR determinations)
Nixon v. State, 2 So. 3d 137 (Fla. 2009) (three-prong MR framework; clear-and-convincing standard not automatic on MR adaptive behavior)
Phillips v. State, 984 So. 2d 503 (Fla. 2008) (applies three-prong test; adaptive behavior concerns must be current)
Jones v. State, 966 So. 2d 319 (Fla. 2007) (defines adaptive behavior prong and concurrent manifestation)
Trotter v. State, 932 So. 2d 1049 (Fla. 2006) (discusses MR standards and evidentiary considerations)
Cherry v. State, 959 So. 2d 702 (Fla. 2007) (establishes standard for IQ/SEM and the 70 threshold under 921.137)