In United States law, ineffective assistance of counsel is a claim raised by a convicted criminal defendant asserting that the defendant's legal counsel performed so ineffectively that it deprived the defendant of the constitutional right guaranteed by the Assistance of Counsel Clause of the Sixth Amendment to the United States Constitution. Having the 'benefit of counsel' or 'assistance of counsel' means that the criminal defendant has had a competent attorney representing them. Competence is defined as reasonable professional assistance and is defined in part by prevailing professional norms and standards.