<P> A grandfather clause (or grandfather policy) is a provision in which an old rule continues to apply to some existing situations while a new rule will apply to all future cases . Those exempt from the new rule are said to have grandfather rights or acquired rights, or to have been grandfathered in . Frequently, the exemption is limited; it may extend for a set time, or it may be lost under certain circumstances . For example, a "grandfathered power plant" might be exempt from new, more restrictive pollution laws, but the exception may be revoked and the new rules would apply if the plant were expanded . Often, such a provision is used as a compromise or out of practicality, to allow new rules to be enacted without upsetting a well - established logistical or political situation . This extends the idea of a rule not being retroactively applied . Another common example of a grandfather clause is a customer of a utility or telecommunications service who pays a certain rate and maintains that rate even if other subscribers and new subscribers face higher or increasing rates . If it is an unlimited clause it continues indefinitely and is only cancelled if the subscriber discontinues the services, fails to pay their bill (s) or makes certain changes to their contract . </P> <P> The term originated in late nineteenth - century legislation and constitutional amendments passed by a number of U.S. Southern states, which created new requirements for literacy tests, payment of poll taxes, and / or residency and property restrictions to register to vote . States in some cases exempted those whose ancestors (grandfathers) had the right to vote before the Civil War, or as of a particular date, from such requirements . The intent and effect of such rules was to prevent poor and illiterate African - American former slaves and their descendants from voting, but without denying poor and illiterate whites the right to vote . Although these original grandfather clauses were eventually ruled unconstitutional, the terms grandfather clause and grandfather have been adapted to other uses . </P> <P> The original grandfather clauses were contained in new state constitutions and Jim Crow laws passed by white - dominated state legislatures from 1890 to 1908 in most of the Southern United States to restrict voter rolls and effectively prevent blacks, Mexican Americans (in Texas), and poor whites from voting . Prohibitions on freedmen's voting in place before 1870 were nullified by the Fifteenth Amendment . </P>

Where does the phrase grandfathered in come from
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