<Tr> <Th_colspan="2"> Laws applied </Th> </Tr> <Tr> <Td_colspan="2"> U.S. Const . amend . VI </Td> </Tr> <P> Strickland v. Washington, 466 U.S. 668 (1984), was a decision by the Supreme Court of the United States that established the standard for determining when a criminal defendant's Sixth Amendment right to counsel is violated by that counsel's inadequate performance . </P> <P> The Court, in a decision by Justice O'Connor, established a two - part test for an ineffective assistance of counsel claim: a criminal defendant must show two things: </P>

4. the concept of attorney competence was defined by the u.s. supreme court in what case