State v. Lambdin, 356 P.3d 165

In August 2009 Dennis Lambdin killed his wife; he conceded the killing but claimed special mitigation by extreme emotional distress (EED) to reduce murder to manslaughter.
The trial court gave seven instructions on EED; Lambdin challenges three (Instructions 19–21) as misstating the law.
Instruction 19 defined EED using the court’s prior-case language requiring an "extremely unusual and overwhelming stress" causing the average reasonable person to "experience a loss of self-control."
Instruction 20 told jurors a triggering event is required but need not be contemporaneous; Instruction 21 directed consideration of "then-existing circumstances," including past experiences.
The jury unanimously found Lambdin failed to prove EED by a preponderance and convicted him of murder; Lambdin appealed, asserting erroneous instructions, prosecutor misconduct in closing, and cumulative error.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether jury instructions misstated law on special mitigation by EED	Instructions correctly stated Utah law and precedent	Instructions improperly required the loss of self-control to be "reasonable," not just that the emotional distress have a reasonable explanation	Held: Instructions correct; EED as judicially defined includes loss of self-control assessed from a reasonable-person perspective
Whether jury could consider pre-existing, non-contemporaneous stressors	Instruction 20–21 properly allowed consideration of prior events and broader context	Instructions conflated EED with heat-of-passion and failed to permit decade-long marital history as context	Held: Instructions 20–21 adequate; jurors could consider past experiences and emotions in assessing EED
Whether prosecutor misstated law in closing by echoing instructions	Prosecutor’s explanation tracked the court’s instructions and was lawful	Prosecutor misinformed jury by emphasizing reasonable loss of self-control	Held: No misconduct; prosecutor’s remarks were consistent with correct instructions
Whether cumulative errors require reversal	No prejudicial errors shown; cumulative-error doctrine not triggered	Multiple errors together undermined trial fairness	Held: No errors found; cumulative-error claim fails

State v. White, 251 P.3d 820 (Utah 2011) (defines EED as extremely unusual, overwhelming stress causing a reasonable person to lose self-control)
State v. Spillers, 152 P.3d 315 (Utah 2007) (EED requires extreme stress leading an average reasonable person to lose self-control)
Ross v. State, 293 P.3d 345 (Utah 2012) (factfinder must consider whether a reasonable person would have experienced extreme reaction and loss of self-control)
State v. Campos, 309 P.3d 1160 (Utah Ct. App. 2013) (external triggering event required; court applies White’s definition)
State v. Drej, 233 P.3d 476 (Utah 2010) (defendant bears preponderance burden to prove mitigation)
State v. Shumway, 63 P.3d 94 (Utah 2002) (discusses relationship between extreme emotional reaction and resulting loss of self-control)
State v. Lee, 318 P.3d 1164 (Utah Ct. App. 2014) (instructions viewed in totality govern appellate review)