argumentum ad antiquatatem (i.e., argument to antiquity / appeal to tradition). This is the argument that essentially says, “x is right because x has always been done that way.”
For example, a plantation owner in 1859 Georgia may have said, “slavery has been a part of our heritage for decades, we need it to keep our way of life alive.” While there may be some truth in the second half of the sentence, clearly the owner is ignoring the human suffering caused by enslavement of one man over another which should necessitate a dramatic change in that “way of life.”
Another more timely example may be heard in the debate over the recent repeal of don’t ask don’t tell. For example, a proponent of the policy may suggest that, “the policy worked for years; therefore we have no business changing it.” However, the data suggests that sexual orientation has no measurable impact on military effectiveness; which renders the policy superfluous and creates an unnecessary environment of fear among gay and lesbian service members.