For discussion of counsel's duties in relation to defences that have no real prospect of success, see Knowles v Mirzayance  USSC No 07-1315 (24 March 2009).
Points of general interest mentioned here are:
- There is no requirement that a defence has to be run if all that can be said for it is that there is "nothing to lose" in running it.
- In alleging deficient representation by counsel, an appellant must show both deficient performance by counsel, and prejudice (ie a reasonable probability that, but for counsel's unprofessional errors, the result of the proceeding would have been different).
- Deficient performance requires that the appellant show that counsel's representation fell below an objective standard of reasonableness.
- Counsel's conduct was virtually unchallengeable where he had made a decision on an informed basis after thorough investigation of law and facts relevant to plausible options.
- There is no prevailing professional norm that counsel must assert the only defence available, even one almost certain to lose.
And another decision of the United States Supreme Court is of general interest for its terminology concerning inappropriate defence tactics: Puckett v United States  USSC No 07-9712 (25 March 2009):
- Sandbagging: a defendant's conduct in remaining silent about his objection and belatedly raising the error only if the case does not conclude in his favour. Cf. Wainwright v. Sykes, 433 U. S. 72, 89 (1977); see also United States v. Vonn, 535 U. S. 55, 72 (2002).
- Gaming the system: instead of pointing out an error in a timely way, "wait[ing] to see if the sentence later str[ikes] him as satisfactory," Vonn, 535 U. S., at 73, and then seeking a second bite at the apple by raising the claim.
And a phrase which is probably new to many people: "hornbook law", used here in the sentence "But it is hornbook law that misrepresentation requires an intent at the time of contracting not to perform." The idea is that this is the sort of law that is hallowed.
In Puckett, it was conceded that a plea bargain had been broken by the prosecution, but the Court found that in the circumstances this did not invalidate the plea of guilty and that there was no prejudice to the appellant as it was he would "likely would not have" (as Americans say) obtained the benefits that the parties had agreed to. He was seeking to use his guilty plea as a sign of contrition, but he had subsequently reoffended so the plea could hardly be said to have come from contrition. Plain error review requires, as held in United States v. Olano, 507 U. S. 725 (1993), (1) an error that has not been waived; (2) the error must be clear or obvious, (3) the error must have affected the appellant's substantial rights – usually in that it affected the result of the proceeding; (4) and, if those requirements are met, a remedy may be given if the error has seriously affected the fairness, integrity or public reputation of judicial proceedings.
But to begin with, the error must be complained of at the earliest opportunity:
""anyone familiar with the work of courts understands that errors are a constant in the trial process, that most do not much matter, and that a reflexive inclination by appellate courts to reverse because of unpreserved error would be fatal." United States v. Padilla, 415 F. 3d 211, 224 (CA1 2005) (en banc) (Boudin, C. J., concurring)."