In the case of United States v. Cuauhtemoc Gonzalez-Lopez (2005), the U.S. Supreme Court ruled in favor of Gonzalez-Lopez, who had been denied his Sixth Amendment right to counsel of choice during a drug trial that resulted in his conviction. The court held that denial of this constitutional right constituted "structural error" and thus required automatic reversal of the conviction, regardless if there was proof that this violation affected the outcome or not. This decision emphasized on protecting defendants' autonomy to choose their own legal representation as an essential component for ensuring fair trials.

In the dissenting opinion for United States v. Cuauhtemoc Gonzalez-Lopez, Justice Alito argued that the majority's decision to overturn a conviction due to a violation of the defendant's Sixth Amendment right to counsel was too extreme. He contended that while it is important for defendants to have their choice of legal representation, this should not automatically lead to an overturned conviction if they are denied this right but still receive competent defense. He believed that there must be proof of prejudice resulting from such denial in order for a trial verdict or sentence to be invalidated. In other words, he felt it necessary for defendants who claim their Sixth Amendment rights were violated by being denied chosen counsel need show how different actions taken by another attorney would likely have resulted in a different outcome at trial.