ACLU History: Mapp v. Ohio

Document Date: September 1, 2010

In 1914, the Supreme Court established the ‘exclusionary rule’ when it held in Weeks v. United States that the federal government could not rely on illegally seized evidence to obtain criminal convictions in federal court. The ruling in Weeks, however, was limited to the federal government. That changed with the Supreme Court’s landmark 1961 decision in Mapp v. Ohio.

The case arose when an Ohio woman, Dollree Mapp, refused to allow local police to enter her home without a warrant in their search for a suspected bombing fugitive. Police eventually tricked their way into the house with a false warrant and, after failing to find the suspect, charged Mapp with possessing ‘lewd and lascivious’ material which they found in a trunk in the basement.

While Mapp’s defense attorney cited the 1914 Weeks case in seeking to dismiss the charges, he failed to argue that this constitutional prohibition against using illegally obtained evidence should be applied in a state court. However, an influential brief filed by the ACLU of Ohio made just this point, and the ACLU attorney who wrote it, Bernard Berkman, ended up arguing the case before the Supreme Court.

In 1961, citing the ACLU’s arguments, the Supreme Court reversed Mapp’s conviction and adopted the exclusionary rule as a national standard. As important as it is to convict criminals, the Supreme Court in Mapp rightly insisted that the Constitution must not be trampled in the process. ‘Nothing can destroy a government more quickly,’ the Court noted, ‘than its failure to observe its own laws, or worse, its disregard of the charter of its own existence.’

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