Customs is the only function I could think of that has greatly weakened in authority. What else could I look at to try and look into the people that backed the major politicians of the time period?
The post office appointed positions are far weaker than they were in the 19th century, the mass of other means by which people can communicate as greatly reduced the power and the Federal government is far larger( in the 19th century the Post Master commanded a substantial amount of patronage). For instance when Monroe appointed Van Renseselear PostMaster of Albany, Martin Van Buren followers who were opposed to Van Renseselear quipped that all future letters " would be advisable that they should send it part of the way by private conveyance or mail their communications this side of Albany".