What is the current state of the law on excluded evidence in criminal cases?

"[T]he general rule [is] that the application of the ordinary rules of evidence under state law do[es] not violate a criminal defendant's federal constitutional right to present a defense, because trial courts retain the intrinsic power under state law to exercise discretion to control the admission of evidence at trial. [Citation.] . . . [] This general rule will give way in extraordinary and unusual circumstances." (People v. Abilez (2007) 41 Cal.4th 472, 503.) Extraordinary and unusual circumstances exist when "the excluded evidence was 'so vital to the defense that due process principles required its admission.' " (Ibid.)

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