Final answer:
Attacking a conviction based on ineffective assistance of counsel involves proving that the counsel's performance was deficient and resulted in prejudice to the outcome of the case, following the guidelines from Strickland v. Washington.
Step-by-step explanation:
When attacking a conviction on the grounds of ineffective assistance of counsel, the legal presumption is based on the two-pronged test established in Strickland v. Washington. To overthrow a conviction, a defendant must demonstrate that counsel's performance was deficient and that this deficiency resulted in prejudice to the client’s case. Specifically, the defendant has to show that the counsel's performance fell below an objective standard of reasonableness and that there is a reasonable probability that, had the counsel provided effective assistance, the outcome would have been different. Additionally, Padilla v. Kentucky mandates that criminal defense attorneys must inform their clients regarding the risk of deportation, depending on the clarity of the law. Competency to stand trial or plead guilty is also a crucial aspect, as recognized in Dusky v. United States and Godinez v. Moran. Finally, the presumption of innocence is a fundamental right of the accused, ensuring that they are considered innocent until proven guilty.