What is seniority? What role does seniority play in determining leadership on congressional committees? How has the value placed on seniority changed over time?

What will be an ideal response?

An ideal response will:
1, Define seniority as the principle that one attains a position on the basis of length of service.
2, Explain that for most of the twentieth century before the 1970s, appointment by seniority was an unbreakable rule: The most senior committee member of the majority party automatically became chair of the committee, and the most senior member of the minority party automatically became the ranking minority member.
3, Note that after 1974, both Republicans and Democrats in the House instituted the secret ballot among party members for the election of chairs, and seniority was occasionally ignored.
4, Note that appointment of committee chairs in the House remains firmly in the hands of majority party leaders today, but in the Senate, seniority continues to be an important criterion for appointment to a chairmanship position.