If a legislator is safe from competition, or if he represents groups with the same economic and political beliefs, he does not have to change his ideas or respond to the needs of the broader population. He can rest content with a mediocre, absentee performance knowing he will be returned to office. And as he is returned year after year the seniority system gives him immense control over people from other parts of the country whose views he need not heed at all.
Edward Moore Kennedy (1968). “Decisions for a Decade: Policies and Programs for the 1970s”, New American Library of Canada