United States v. Booker, Supreme Court of the United States, January 12, 2005 [applying Blakely v. Washington and holding that the federal sentencing guidelines are subject to the Sixth Amendment and that the current guidelines under which judges can impose "enhanced sentences" on the basis of facts not found by the jury are no longer mandatory]. Excerpt [per Justice Stevens]:

The question presented in each of these cases is whether an application of the Federal Sentencing Guidelines violated the Sixth Amendment. In each case, the courts below held that binding rules set forth in the Guidelines limited the severity of the sentence that the judge could lawfully impose on the defendant based on the facts found by the jury at his trial. In both cases the courts rejected, on the basis of our decision in Blakely v. Washington, 542 U.S. ___ (2004), the Government's recommended application of the Sentencing Guidelines because the proposed sentences were based on additional facts that the sentencing judge found by a preponderance of the evidence. We hold that both courts correctly concluded that the Sixth Amendment as construed in Blakely does apply to the Sentencing Guidelines. In a separate opinion authored by Justice Breyer, the Court concludes that in light of this holding, two provisions of the Sentencing Reform Act of 1984 (SRA) that have the effect of making the Guidelines mandatory must be invalidated in order to allow the statute to operate in a manner consistent with congressional intent.

Review the full ruling here [PDF], including a partial opinion by Stevens [PDF], a partial dissent by Scalia [PDF], a partial dissent by Thomas [PDF], a partial dissent by Breyer, and a partial dissent by Stevens [PDF].