One of the basic tenets of the relationship between an attorney and the client is that any information which passes between the two remains confidential. This concept is also known as the attorney client privilege. Based on early English common law, the idea of privilege is a simple one - a client maintains the privilege to refuse to disclose or to have an attorney disclose any communications that occur while one is seeking legal advice.
This privilege is important as it allows a client the comfort to disclose all necessary factual information to an attorney without fear that such discussions will harm the client's case. While an attorney may invoke the privilege on behalf of a client, the right originates with the client. The client, and not the attorney decides which information is confidential and should remain privileged and advises the attorney accordingly.
In the well known 1950 case of United States v. United Shoe Machinery Corp, the court defined the requirements for attorney-client privilege as follows:
Courts may make exceptions to the above if they find that great harm is caused to the other side by upholding the privilege. It is important to remember that a court may force disclosure of certain facts and that privilege will never apply to any communication concerning commitment or intent to commit a fraud or a crime. Further, the privilege does not apply when an attorney is acting as a business advisor (i.e. board member) to a company.
In the early 1990's, the federal government began to narrow the attorney-client privilege in an attempt to fight the war on drugs. The feds pushed a policy that made attorneys disclose the name and amount of cash payments made by clients in excess of $10,000. While numerous cases, including United States v. Leventhal, fought this policy, courts have long upheld the government's right to this information.
States may also apply different client-attorney privilege law. In Washington state, the privilege only protects client communications; whereas in California, the communications of an attorney are considered privileged no matter what.
Attorney-client privilege remains one of the most important elements governing a legal relationship. No matter what happens on the court room floor, in a lawyer's office everything is confidential and clients can feel free to be completely honest.