11.   Senate rules make it possible for one member to block legislation, particularly in the days before Congress adjourns for elections.

12.   Senate rules permit individual senators to impede legislation.

13.   Senate rules require all testimony to be in public, and the Senate Historical Office says no impeachment trial has ever been held without public witnesses.

14.   Senate rules require impeachment deliberations to be conducted behind closed doors, and senators have soundly rejected two attempts in the trial to open debate on procedural motions.

15.   Senate rules require that the final bills considered by both chambers be identical.

16.   Senate ethics rules prohibit senators from divulging what is said in these sessions.

17.   Senate impeachment rules provide for an open trial but would require deliberations on procedural questions, motions or on a verdict to be done behind closed doors.

18.   Senate rules allow members to submit remarks for the record.

19.   Senate rules do not require that its members excuse themselves in cases in which they may have a conflict of interest.

20.   Senate rules prevent one member from chairing two committees at once.