Duhaime's Law Dictionary

Deficient Definition:

USA constitutional law: the substandard performance of an attorney.

Related Terms: Ineffective Assistance, Sixth Amendment

In American constitutional law (Sixth Amendment), an accused person is entitled to the assistance of counsel. To this, the courts have read in a requirement for effective assistance of counsel and where such assistance is not effective, it is referred to, in law, as ineffective assistance, for which the first component is that the lawyer's assistance was deficient (the other being a finding of prejudice upon the accused).

For example, in Strickland, Justice Pryor of the United States Court of Appeals wrote:

"To prevail on a claim of ineffective assistance, a defendant must establish two things: (1) counsel's performance was deficient, meaning it fell below an objective standard of reasonableness; and (2) the deficient performance prejudiced the defendant."

In the 2008 decision of Dale v Quarterman, the United States Court of Appeals attempted a codification of the law in this regards including the concept of assessing that objective standard by reference to "prevailing professional norms":

"To prove ineffective assistance, a defendant must show that counsel was deficient, and the deficiency prejudiced his defense.

"Counsel's representation is deficient if it fell below an objective standard of reasonableness measured by prevailing professional norms. The reviewing court must strongly presume that counsel rendered adequate assistance and that the challenged conduct was the product of reasoned trial strategy.

"Prejudice is a reasonable probability that but for counsel's unprofessional errors, the result of the proceeding would have been different. A reasonable probability is a probability sufficient to undermine confidence in the outcome and is less than a preponderance of the evidence. In the state sentencing context, the relevant inquiry is whether, absent counsel's errors, there is a reasonable probability that the defendant's sentence would have been significantly less harsh, taking into account such factors as the defendant's actual sentence, the potential minimum and maximum sentences that could have been received, the placement of the actual sentence within the range of potential sentences, and any relevant mitigating or aggravating circumstances."

There is, circa 2010, another line of American jurisprudence that suggests another definition of deficient for the purposes of the Sixth Amendment.

For example, consider these words of Justice Martin of the Supreme Court of North Carolina in State v Taylor:

"Performance is deficient when counsel's representation falls beneath an objective standard of reasonableness, or when counsel's errors are so serious that counsel was not functioning as the counsel guaranteed the defendant by the Sixth Amendment."


  • Dale v. Quarterman, 553 F. 3d 876 (2008). Re "measured by prevailing professional norms", see also del Toro v Quarterman, 498 F. 3d 486 (USCA, 2007) or Daily v State, 965 So. 2d 38.
  • Duhaime, Lloyd, Legal Definition of Ineffective Assistance
  • Gordon v. US, 518 F. 3d 1291 (2008)
  • State v. Taylor, 669 SE 2d 239 (2008); See also State v. Eyre, 2008 UT 16; also at 179 P. 3d 792 (Supreme Court of Utah, 2007) or Benvenuto v. State, 165 P. 3d 1195 (Supreme Court of Utah, 2007)

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