The United States Supreme Court here held that the Seventh Circuit Court of Appeals erred in engrafting onto the analysis of an ineffective assistance of counsel claim under Strickland v. Washington (1984) 466 U.S. 668, an additional requirement that to prove prejudice, an increase in the term of imprisonment must be “significant.” Although the amount by which a defendant’s sentence is increased by a particular decision may be a factor to consider in determining whether counsel’s performance in failing to argue the point constitutes ineffective assistance, it cannot serve as a bar to a showing of prejudice. Here, the increase in sentence of at least 6 months, and possibly by as many as 21 months, occasioned by counsel’s failure to make a mitigating argument under the federal sentencing guidelines, satisfied the prejudice test of Strickland.