Responsibility for the enforcement of the laws against crime traditionally fell on the states and the local authorities. The federal government's involvement was, by law and custom, limited mostly to enforcement of laws governing the collection of tariffs and taxes, regulation and operation of the mails', and the maintenance of order in the nation's territories and possessions. In 1914 the Supreme Court inadvertently created a loophole in the rules of evidence that shifted the burden of enforcing the laws even more squarely onto the shoulders of local law enforcement officials, where it would remain for at least two decades more.

When Fremont Weeks was arrested by Kansas City police officers on a gambling charge, he was taken into custody at his place of employment some distance from his home. The evidence the police found was turned over to the federal marshal and...