The Fourth Amendment to the United States Constitution prohibits unreasonable searches and seizures. Yet as interpreted by the United States Supreme Court, the Amendment places no restriction on police combing through financial records; telephone, e-mail and website transactional records; or garbage left for collection. Indeed there is no protection for any information knowingly provided to a third party, because the provider is said to retain no reasonable expectation of privacy in that information. As technology dictates that more and more of our personal lives are available to anyone equipped to receive them, and as social norms dictate that more and more information is provided to third parties, this restriction threatens to render the Fourth Amendment a practical nullity. By reviewing some modern technologies (e-mail, millimeter wave concealed weapons detectors, off-the-window eavesdropping, and TEMPEST receivers) we can appreciate the magnitude of the issue and determine how Fourth Amendment jurisprudence must be altered in order to better balance privacy and security in the post-9/11 United States. We must craft definitions of search and reasonableness that account for the impending world in which all information is available to those equipped to receive it. Although restricting the Supreme Court's third party doctrine is a step in the right direction, a better solution is to jettison the doctrine entirely and to rely on a totality-based doctrine of reasonableness. Only in this manner can courts preserve the aims of the Fourth Amendment despite dramatic changes in the technological backdrop.