As per the title, is a defense lawyer who knows, for certain, that a client is guilty, (e.g. the client says so, etc.) obligated to try and prove innocence? What is a defense lawyer obligated to do in such circumstances?

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    A client saying so does not mean that a lawyer knows for certain that the client is guilty; a signed confession does not constitute absolute proof either (and people do all sorts of crazy things against their best interest). "Guilt" often involves assessing mental state (e.g. "reasonable fear"), plus a careful reading of the law. Being an actual witness to the crime is really the only way to be be absolutely certain about the event. It would help if you fleshed out the question, to separate "suspect that he is guilty" from "know it".
    – user6726
    Apr 20, 2017 at 14:35
  • Let's say that the defendant basically says that the facts of the complaint against him are true, to the lawyer, and the lawyer knows or otherwise has no reason to believe the client is or was under duress or an altered mental state.
    – Stackstuck
    Apr 20, 2017 at 14:53
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    nolo.com/legal-encyclopedia/… Apr 20, 2017 at 15:04
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    I guess you mean a criminal case. There the burden of proof is on the accusation side, so the defense lawyer does not need to prove that his client is innocent; he only needs to show that the charges against his client are not supported by the evidence presented. Think that the juries do not declare somebody "innocent", they declare him "not guilty".
    – SJuan76
    Apr 20, 2017 at 15:29
  • The lawyer is still there to make sure the defendant is treated fairly. Even if their client admits to them that they're guilty, a defense attorney is still responsible for making sure they are only found guilty of the actual crime and that the prosecution does not pad charges or attempt to do something unethical themselves. Defense is not about trying to let a person get away with a crime like some people believe. It is about ensuring a person gets a fair trial, which should inherently get them found not guilty if they aren't guilty.
    – animuson
    Apr 21, 2017 at 7:10

2 Answers 2


To know a defendant is guilty is to know that the government has convinced a judge or jury beyond a reasonable doubt that the defendant committed all the elements of a crime.

A lawyer can't know that the government will accomplish this prior to a trial.

Options for a lawyer who determines that the government has a strong case include:

  • seeking to have evidence excluded
  • looking for other grounds for appeals
  • establishing affirmative defenses
  • negotiating a plea deal for a lighter sentence or less serious crime
  • the lawyer will continue to force the government to prove their case
  • Suppose that a lawyer becomes convinced (after taking on the client) that his client is guilty: what prevents him from withdrawing from the case, or revealing that evidence to the prosecution? What happens if a lawyer had prior knowledge of wrong-doing, e.g. Murdoch Esq. previously witnesses Castle committing murder? Once he take on the client, can / must he reveal evidence that he was aware of prior to taking on the client?
    – user6726
    Apr 20, 2017 at 15:49
  • There is nothing ethically wrong with presenting a full and strong defense in a case where the factual allegations of the prosecution happen to be true. Indeed, the defense lawyer is obliged to do so. The only limitation is that in this circumstance the lawyer can't present testimony to the court that the lawyer knows is perjured. Also, a defense lawyer can ethically seek jury nullification.
    – ohwilleke
    Apr 20, 2017 at 16:21
  • That was actually an invite to expand on the answer: why can't a lawyer bail if he thinks (knows) the client is guilty; is an attorney obliged to reveal inculpatory evidence not coming from attorney-client relation?
    – user6726
    Apr 20, 2017 at 16:24
  • @user6726 a lawyer who is a witness to an alleged crime cannot act for either the prosecution or the defence
    – Dale M
    Apr 20, 2017 at 21:03

Defendants (and their lawyers) need to prove nothing: the onus is on the prosecution to prove guilt beyond reasonable doubt. That is why defendants are found guilty or not guilty - they are never found innocent.

That said, while jurisdictions vary, the NSW Barrister's Rules are representative of the obligations of an advocate in common law jurisdictions. Of note:

Duty to the Court

  1. A barrister has an overriding duty to the Court to act with independence in the interests of the administration of justice.
  2. A barrister must not deceive or knowingly or recklessly mislead the Court.
  3. A barrister must take all necessary steps to correct any misleading statement made by the barrister to a court as soon as possible after the barrister becomes aware that the statement was misleading.
  4. A barrister must, at the appropriate time in the hearing of the case if the court has not yet been informed of that matter, inform the court of:

    (a) any binding authority;

    (b) where there is no binding authority any authority decided by an Australian appellate court; and

    (c) any applicable legislation;

    known to the barrister and which the barrister has reasonable grounds to believe to be directly in point, against the client’s case.

Duty to client

  1. A barrister must promote and protect fearlessly and by all proper and lawful means the client’s best interests to the best of the barrister’s skill and diligence, and do so without regard to his or her own interest or to any consequences to the barrister or to any other person.

  2. A barrister must inform the client or the instructing solicitor about the alternatives to fully contested adjudication of the case which are reasonably available to the client, unless the barrister believes on reasonable grounds that the client already has such an understanding of those alternatives as to permit the client to make decisions about the client’s best interests in relation to the litigation

  3. A barrister must seek to assist the client to understand the issues in the case and the client’s possible rights and obligations, sufficiently to permit the client to give proper instructions, including instructions in connection with any compromise of the case.

  4. A barrister must (unless circumstances warrant otherwise in the barrister’s considered opinion) advise a client who is charged with a criminal offence about any law, procedure or practice which in substance holds out the prospect of some advantage (including diminution of penalty), if the client pleads guilty or authorises other steps towards reducing the issues, time, cost or distress involved in the proceedings.

Criminal pleas

40A. It is the duty of a barrister representing a person charged with a criminal offence:

(a) to advise the client generally about any plea to the charge; and

(b) to make clear that the client has the responsibility for and complete freedom of choosing the pleas to be entered.

40B. For the purpose of fulfilling the duty in rule 40A, a barrister may, in an appropriate case, advise the client in strong terms that the client is unlikely to escape conviction and that a plea of guilty is generally regarded by the court as a mitigating factor to the extent that the client is viewed by the court as cooperating in the criminal justice process.

40C. Where a barrister is informed that the client denies committing the offence charged but insists on pleading guilty to the charge, the barrister;

(a) must advise the client to the effect that by pleading guilty, the client will be admitting guilt to all the world in respect of all the elements of the charge;

(b) must advise the client that matters submitted in mitigation after a plea of guilty must be consistent with admitting guilt in respect of all of the elements of the offence;

(c) must be satisfied that after receiving proper advice the client is making a free and informed choice to plead guilty; and

(d) may otherwise continue to represent the client.


  1. A barrister must not act as the mere mouthpiece of the client or of the instructing solicitor and must exercise the forensic judgments called for during the case independently, after the appropriate consideration of the client’s and the instructing solicitor’s wishes where practicable.

So a barrister's duty if they believe the client is likely to be proven guilty is to advise them of this and point out that this is a mitigating factor in sentencing. Notwithstanding, a barrister is never permitted to deceive the court or allow the court to be deceived - this almost certainly means that a barrister will not call the defendant as a witness if the barrister believes the client will perjure themselves.


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