Swarthout v. Cooke, 562 U.S. 216

California parole statute gives the Board authority to release when eligible unless public safety requires longer incarceration; review is by state habeas if parole denied.
California Supreme Court has held an inmate’s release is warranted if some evidence supports unsuitability due to current danger.
Cooke (1991 conviction for attempted first-degree murder) was denied parole in 2002 based on the offense’s cruelty, rehabilitation failures, skill deficits, and misconduct, despite a favorable psychological report later deemed credible by the board as not credible.
Cooke’s state habeas petitions were denied; federal petition under 28 U.S.C. § 2254 challenged the parole denial; Ninth Circuit held California’s some-evidence rule created a federal liberty interest and reviewed for reasonableness of facts.
Clay (1978 murder) was deemed unsuitable by the Governor after the Board found him suitable in 2003; federal court reversed the Governor’s decision and Ninth Circuit affirmed that the Governor’s reliance on the long-ago offense was improper; broader state-law questions remained.
The Supreme Court held that federal habeas relief may not rest on state-law error and that due-process review of parole is limited to minimal procedures; California’s some-evidence rule is not a federal constitutional requirement.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether federal habeas relief lies for alleged misapplication of state parole law.	Cooke argues federal review can correct state-law misapplication.	States may create liberty interests and procedures; federal review limited to constitutional due process.	No federal-habeas relief for state-law errors; only due-process questions are reviewable.
Whether California’s 'some evidence' standard is a federal due-process requirement.	Some evidence is a component of the federal liberty interest in parole.	Due process requires only minimal procedures; California’s standard is state-law, not federal law.	The 'some evidence' rule is not a federal due-process requirement.

Greenholtz v. Inmates of Neb. Penal and Correctional Complex, 442 U.S. 1 (1979) (parole procedures must be fair but need not be more than opportunity to be heard and reasons for denial)
Board of Pardons v. Allen, 482 U.S. 369 (1987) (parole decisions and due process considerations)
Engle v. Isaac, 456 U.S. 107 (1982) (mere state-law error not a due-process violation)
Estelle v. McGuire, 502 U.S. 62 (1991) (federal habeas relief not for state-law errors)
In re Rosenkrantz, 29 Cal. 4th 616 (2002) (California good-time/Parole review context cited but not federal-law-centered)
Hayward v. Marshall, 603 F.3d 546 (9th Cir. 2010) (en banc; California parole procedure framework; minimal due-process standard)