The role of a defense attorney is to protect the rights of a person accused of a crime and to fight for the best possible outcome at every stage of the case. That work starts the moment police want to talk and runs through investigation, plea negotiations, trial, sentencing, and appeal. It is grounded in the Sixth Amendment, which guarantees every person facing criminal prosecution the right to have a lawyer assist in their defense and requires the court to appoint one at no cost when the accused cannot afford to hire counsel.1Library of Congress. U.S. Constitution – Sixth Amendment
Everything else a defense attorney does flows from that guarantee. The right attaches once the government shifts from investigation to accusation, meaning the first formal charging proceeding, whether that is an indictment, arraignment, information, or preliminary hearing.2Cornell Law School. Right to Counsel From that point forward, the lawyer is the client’s shield against the full weight of the state.
Protecting Constitutional Rights
Before anything resembling a trial, a defense attorney spends real energy on two other constitutional protections that law enforcement bumps into constantly: the right against self-incrimination and the right against illegal searches.
The Right to Remain Silent
The Fifth Amendment protects you from being compelled to be a witness against yourself in a criminal case.3Cornell Law School. Fifth Amendment In practice, that means you can refuse to answer police questions, and your silence cannot be used as evidence of guilt. An attorney tells you when and how to invoke the right, because the line between a voluntary conversation and a coerced statement is thinner than most people realize. Anything you say before invoking silence can and will be used against you, which is why defense attorneys almost universally tell clients to say nothing to police without a lawyer present.4Cornell Law School. Fifth Amendment
Challenging Illegal Searches
The Fourth Amendment protects you from unreasonable searches and seizures and requires warrants to be based on probable cause.5Legal Information Institute. Fourth Amendment – U.S. Constitution A defense attorney reviews every piece of evidence the prosecution plans to use and asks hard questions about how it was obtained. Was there a warrant? Did it specifically describe what could be searched? If there was no warrant, did a recognized exception actually apply?
When law enforcement cuts corners, the attorney’s primary weapon is a motion to suppress. This is rooted in the exclusionary rule, which prevents the government from using evidence gathered in violation of the Constitution. The rule reaches evidence obtained through unreasonable searches under the Fourth Amendment, improperly obtained statements under the Fifth Amendment, and violations of the Sixth Amendment right to counsel.6LII / Legal Information Institute. Exclusionary Rule Winning a suppression motion can gut the prosecution’s case. If the drugs were found during an illegal search, the drugs are out. If the confession came without proper Miranda warnings, the confession is out. Many cases are actually decided here, long before a jury is seated.
Investigating the Case
A defense attorney conducts an independent investigation rather than accepting the police version of events. The foundation of that work is discovery, the formal process of obtaining the evidence the prosecution has gathered. Under the federal rules, the defense can request the defendant’s own statements, inspect physical evidence, and review the results of any scientific tests or examinations the government plans to use at trial.7Cornell Law Institute. Federal Rules of Criminal Procedure Rule 16 – Discovery and Inspection
Prosecutors also have a separate constitutional duty to hand over evidence that helps the defense. Under the rule established in Brady v. Maryland, the prosecution must disclose any evidence favorable to the accused that is material to guilt or punishment, and a prosecutor who suppresses such evidence violates the defendant’s right to due process regardless of whether the suppression was intentional.8Justia. Brady v. Maryland, 373 U.S. 83 (1963) A good defense attorney does not wait for this material to arrive. They file specific requests, follow up, and flag potential Brady evidence the prosecution may have overlooked or withheld.
Beyond what the prosecution turns over, the defense team builds its own factual record. That means interviewing witnesses the police never talked to, visiting the scene, pulling surveillance footage, and examining physical evidence independently. In cases built on forensic evidence, the attorney may hire DNA analysts, toxicologists, or accident reconstruction specialists to challenge the government’s conclusions or offer another explanation. The goal is not just to poke holes in the state’s story but to construct a competing version of events.
Counseling the Client
A defense attorney is a counselor in the fullest sense. That means explaining the charges, evaluating the strength of the prosecution’s evidence, and walking through every realistic outcome from acquittal to the maximum sentence. Clients make better decisions when they understand how local judges tend to sentence, what prosecutors in the jurisdiction typically offer, and how a jury is likely to see the facts.
This relationship runs on honesty, and honesty requires confidentiality. Attorney-client privilege protects communications between a lawyer and client that relate to legal advice or services, covering verbal discussions, emails, text messages, and written correspondence.9LII / Cornell Law School. Attorney-Client Privilege The privilege exists so you can tell your attorney everything without fear it will be repeated. An attorney working with incomplete information is building a defense with one hand tied behind their back.
Certain decisions belong to the client alone. Whether to plead guilty, whether to testify, and whether to accept a plea offer are the client’s calls. The attorney’s job is to make sure those decisions are informed, grounded in a clear-eyed assessment of risk rather than fear or wishful thinking.
Negotiating with the Prosecution
Most criminal cases never reach trial. Researchers estimate that roughly 90 to 95 percent of both federal and state cases are resolved through plea bargaining.10Bureau of Justice Assistance. Plea and Charge Bargaining Research Summary That makes negotiation one of the most consequential things a defense attorney does. A skilled negotiator can mean the difference between a felony conviction and a misdemeanor, or between prison and probation.
In a plea bargain, the defendant pleads guilty or no contest to a charge and in return receives some concession from the prosecution. That concession might be a reduced charge, a dismissed count, or an agreed sentencing recommendation. The attorney’s leverage comes from weaknesses in the prosecution’s case, the cost and uncertainty of trial for both sides, and any mitigating facts about the client’s background.
Before accepting any guilty plea, the judge must personally address the defendant and confirm that the plea is voluntary, that the defendant understands the rights being waived, and that a factual basis supports the plea.11Cornell Law Institute. Federal Rules of Criminal Procedure Rule 11 – Pleas The defense attorney prepares the client for that colloquy so nothing comes as a surprise.
For some defendants, the best outcome is not a reduced charge but no conviction at all. Pretrial diversion programs allow eligible people to complete conditions like counseling, community service, or substance abuse treatment in exchange for having the charges dropped. In the federal system, U.S. Attorneys have discretion to divert individuals when a prosecutable case exists, and prosecutors often prioritize young offenders, veterans, and those with substance abuse or mental health challenges. Certain categories are excluded, including offenses involving serious bodily injury, firearms, child exploitation, terrorism, and public corruption.12United States Department of Justice. 9-22.000 – Pretrial Diversion Program An attorney who knows the local diversion options can steer a client toward that path before the case gains momentum toward trial.
Representing the Client at Trial
When negotiation fails or the client chooses to fight, the defense attorney becomes a trial lawyer. The work starts well before opening statements. Pretrial motions can shape the entire trial by keeping damaging evidence out or narrowing the charges the jury will consider.
Jury Selection
Picking a jury is more art than science, and defense attorneys invest serious effort in voir dire. Both sides question potential jurors about their backgrounds, biases, and ability to be fair. The defense can challenge jurors for cause by arguing a specific bias, and can also use a limited number of peremptory challenges to excuse jurors without stating a reason, though neither side may discriminate based on race or gender.13United States Department of Justice. Trial Experienced defense attorneys know that jury selection is really jury deselection. You are trying to remove the people most likely to convict, not find twelve fans of your client.
Cross-Examination and Presenting the Defense
During trial, the attorney challenges the prosecution’s evidence through cross-examination, which tests the credibility and reliability of each witness. Cross-examination is limited to the subjects covered on direct and matters affecting the witness’s credibility.14Cornell Law Institute. Federal Rules of Evidence Rule 611 A well-executed cross can expose lies, reveal gaps in memory, highlight bias, or show that a witness simply does not know what they claim to know.
The defense also presents its own case when the facts support it, calling witnesses and introducing evidence that supports the client’s version of events or raises reasonable doubt. The attorney frames the narrative through opening and closing arguments, reminding the jury that the burden of proof rests entirely on the prosecution and never shifts to the defense.
Arguing at Sentencing
If a conviction occurs, the attorney’s role does not end. Sentencing is a distinct phase with its own rules and stakes. In federal court, judges must impose a sentence that is “sufficient, but not greater than necessary” to serve the purposes of punishment, considering the nature of the offense, the defendant’s history and characteristics, the need for deterrence, public safety, and the need to avoid unwarranted disparities among similar defendants.15GovInfo. 18 U.S.C. 3553 – Imposition of a Sentence
The defense attorney builds a sentencing presentation around those factors, typically through a written sentencing memorandum that presents the client as a full human being rather than a case number. The memorandum covers personal history, employment, family circumstances, mental health background, and any evidence of rehabilitation or remorse. Character letters from family, employers, and community members carry weight. In serious cases, the defense team may hire a mitigation specialist to investigate the client’s life history for factors like childhood trauma, untreated mental illness, or military service that help explain the conduct without excusing it. The attorney also argues legal points, including requests for departures from sentencing guidelines when circumstances justify it. A compelling presentation can mean the difference between prison and probation, or between five years and fifteen.
Handling Appeals and Post-Conviction Challenges
After a conviction and sentence, the defendant has the right to appeal. In the federal system, the notice of appeal must be filed within 14 days of the judgment.16Legal Information Institute. Federal Rules of Appellate Procedure Rule 4 – Appeal as of Right, When Taken Missing that deadline can forfeit the appeal entirely, which is why a defense attorney flags it immediately after sentencing. If certain post-trial motions are filed, such as a motion for a new trial or a motion for acquittal, the clock resets to 14 days after the court rules on the last pending motion.
An appeal is not a second trial. The appellate court reviews the trial record for legal errors, not factual disputes. Common grounds include improper admission or exclusion of evidence, incorrect jury instructions, prosecutorial misconduct, and constitutional violations during the proceedings. The attorney identifies these errors, briefs the legal arguments, and in some cases presents oral argument to the appellate panel.
One important post-conviction claim is ineffective assistance of counsel, which allows a defendant to argue that trial counsel’s performance was so deficient that it violated the Sixth Amendment. The standard comes from Strickland v. Washington, which requires the defendant to prove two things: that the attorney’s conduct fell below an objective standard of reasonableness, and that the deficient performance created a reasonable probability that the outcome would have been different.17LII / Legal Information Institute. Ineffective Assistance of Counsel Both prongs must be met. The bar is deliberately high and courts give trial attorneys considerable deference, but the claim exists as a safety net for defendants whose lawyers genuinely failed them.
What a Defense Attorney Will Not Do
Defense attorneys operate under professional rules that sometimes create tension with the duty to advocate zealously. Understanding those limits helps explain why defense attorneys do certain things and refuse to do others.
Keep Your Confidences, With Narrow Exceptions
A lawyer cannot reveal information related to the representation of a client unless the client gives informed consent or a narrow exception applies. Those exceptions allow disclosure only in extreme circumstances, such as preventing reasonably certain death or substantial bodily harm, or preventing the client from committing a crime or fraud using the lawyer’s services that would cause substantial financial injury.18American Bar Association. Rule 1.6 – Confidentiality of Information Outside those situations, what you tell your lawyer stays with your lawyer. The ethical duty of confidentiality is broader than the evidentiary privilege and covers all information relating to the representation, regardless of the source.
Avoid Divided Loyalties
A defense attorney cannot represent you if their loyalty is divided. Conflicts arise when the attorney’s interests, or the interests of another client, conflict with yours. The clearest example is representing two co-defendants whose defenses contradict each other. If one client’s best strategy involves blaming the other, the attorney cannot effectively serve both. When a potential conflict exists, the attorney must disclose it and can only proceed with written, informed consent from all affected clients.19LII / Legal Information Institute. Conflict of Interest
Refuse to Present Perjury
A defense attorney cannot knowingly help a client lie under oath. If the attorney knows the client intends to testify falsely, the attorney must first try to persuade the client not to do it. If that fails, the attorney must refuse to present the false testimony. If the attorney discovers the perjury only after it happens, they must take reasonable remedial steps, which can include disclosing the problem to the court.20American Bar Association. Rule 3.3 – Candor Toward the Tribunal The Supreme Court has held that an attorney’s ethical duty to prevent perjury outweighs the duty of zealous advocacy, and that refusing to cooperate with a client’s perjury does not violate the Sixth Amendment.2Cornell Law School. Right to Counsel
The standard matters. The attorney must know the testimony is false, not merely suspect it. A lawyer who reasonably believes a client’s testimony might be false must still allow the defendant to testify. Only actual knowledge triggers the obligation to refuse. That distinction preserves the defendant’s right to tell their story while drawing a firm line at knowingly presenting lies to a court.