This is pulled from a link below, but it deserves highlighting:
1.Archaic rules, such as not allowing committees to hold hearings after 2:00 in the afternoon without unanimous consent.
2.Senators spending less time in Washington, due primarily to fundraising needs, but also owed to anti-Washington sentiment.
3.Proliferation of staffers, often “more ideological than their bosses, and less dependent on institutional relationships.”
4.Lack of actual conversations; Senators never change their minds as a result of the argument of a colleague.
5.“Tabloid” Hill rags (Roll Call, The Hill, Politico, etc…) that promote conflict; fewer state newspapers covering hometown Senators.
6.More Senators coming from the House, not from governorships or other positions that would encourage bipartisanship.
7.Lack of friendships and trust among members (see reasons 2, 4, and 6).
8.The “Quayle generation.” In 1981, more than half of the Senate had served less than 6 years.
9.C-Span, and the new priority of transparency over deal-making.
10.Proliferation of lobbyists (coinciding with the advent of C-Span).
11.Liberal Republicans started vanishing. Southern Democrats died off and were replaced by conservative Republicans. Each party became more insular.
12.Filibusters being used for political purposes.
13.Revolving door from Senate to lobbying firms.
14.Lunching in the caucus rooms as opposed to Senate dining rooms.