In the area of criminal law, defense litigation refers to the various legal tactics employed by attorneys during the course of their representation of defendants. In the United States, those arrested and charged with a crime are afforded due process protections guaranteed by the Constitution. The nature and extent of legal action taken by a defense lawyer on behalf of his client, to a certain degree, will depend on whether the police and the prosecutor have scrupulously followed these constitutional procedural safeguards.
In some cases, a criminal attorney may present a legal argument that asserts that due process violations have occurred, this may result in dismissal of the charges against his client. For example, if there are sufficient facts to support a finding that the police lacked probable cause to arrest his client, a court may order that the charges be dropped. Similarly, if any evidence was unlawfully obtained, such as because police exceeded the permissible scope of a search warrant issued by a judge, a defendant’s attorney will argue that any evidence obtained should be excluded. In some circumstances, these defects may impede to the prosecution’s ability to try its case before a jury.
The standard of proof required for a criminal conviction is evidence that indicates the accused is guilty beyond a reasonable doubt. During trial, the principal strategy of defense litigation is to raise sufficient questions, in the minds of jurors, as to whether the prosecution has met this burden. A common defense litigation tactic is to attempt to undermine the credibility of the prosecution's witnesses, through rigorous cross-examination. In many instances, some of the key witnesses for the prosecution will have received inducements to testify in the form of a reduced sentence or immunity from prosecution. A defendant’s attorney will attempt to portray the testimony of such witnesses as unreliable and untrustworthy, because of this benefit that they have received in exchange for their testimony.
If a jury convicts a defendant, defense litigation procedures would entail reviewing possible grounds for overturning the verdict. A criminal lawyer would review the trial transcript in order to learn if there are any legitimate grounds for an appeal. These may include errors committed by the trial judge, such as the allowing of certain evidence or testimony that was prejudicial to the defendant. An appellate court may order a new trial if it finds that the trial judge committed errors of law in conducting the proceedings, such that the defendant was precluded from receiving a fair trial.