Why do members of congress involve themselves in casework?

it is work that legislators do to their constituents address a problem, and involving themselves in it members of congress win popular support and observe how effectively the executive branch is handling government programs.

it is work that legislators do in committees to edit or revise the language of a bill, and involving themselves in it members of congress increase the chances of their bills being passed and being turned into laws.

it requires legislators to travel to foreign countries to address issues related to american interests, and involving themselves in it members of congress gain credibility and respect among their peers and the american electorate.

it involves criminal cases in which federal laws are broken, and involving themselves in it members of congress better understand what bills to support and what bills to reject.