Prism allows the government unprecedented access to all your personal information, for at least six years. It is a code name for the US government used in surveillance of the nation. In 2007 there were leaked documents that went into effect thus it has gained momentum ever since the purpose mainly is to monitor the potentially valuable communication that are foreign and they pass through the US servers ,the scope is much greater than it appears in practically.
It has helped to deal with issues of security even before they start. The first partner incorporated for Prism was Microsoft and steadily other companies followed like apple. These companies apparently have to hand in data to the government when the need arises to collect information from the servers or they will face a government lawsuit and what’s more is that they get paid to give this information.
Prism monitors direct calls they collect the metadata, concerning to and where phone calls were made to and where they were made from inclusive of the generalized information, what's more is that they have the full access of all the emails or chats sent. This ensures that what is emitted does not compromise national security.
It is not illegal to get this information for the government and if you think they can revoke this, well not really as they have had the authority to do it for years to seek information for the security of the nation and the government. Prism has been embraced even by the US government. It is legal and it is being used to the full core, prism has a full legal standing and it has to be followed to the letter and in no way is it being changed for anything else. The argument is that the nation is far much bigger than individuals who do not approve of prism, indeed it is here to stay we just might need to find a way and live with it.