In the case of Kansas v. Michael Lee Marsh II, 2005, the U.S. Supreme Court examined whether a state law in Kansas violated the Eighth and Fourteenth Amendments by directing imposition of death penalty when mitigating and aggravating circumstances were found to be in equipoise (equal weight). The defendant, Michael Lee Marsh II was convicted for murder and arson resulting in deaths of a woman and her daughter. He was sentenced to death under this law but appealed his sentence arguing that it unconstitutionally favored capital punishment. The Kansas Supreme Court agreed with him stating that if both factors are equally balanced then jury must acquit or convict on lesser charge which is not possible under current statute hence it's unconstitutional. However, U.S Supreme court reversed this decision holding that since there’s no constitutional requirement demanding juries to find beyond reasonable doubt that aggravation outweighs mitigation before imposing death penalty; therefore such laws do not violate due process clause nor does it create presumption favoring death penalty.

In the dissenting opinion for Kansas v. Michael Lee Marsh, II, Justice David H. Souter argued that the Kansas death penalty law was unconstitutional because it allowed a jury to impose a death sentence even when mitigating and aggravating factors were equally weighted. He contended that this violated the Eighth Amendment's prohibition against cruel and unusual punishment by creating too great a risk of arbitrary imposition of capital punishment. The justice also criticized the majority's decision as inconsistent with previous Supreme Court rulings which required juries in capital cases to give "independent weight" to mitigating factors rather than simply comparing them numerically with aggravating circumstances.