Is a trial of impeachment held with or without a jury? How about treaties? And murder?

Answer 1

Forget about the treaties part.

Answer 2

An impeachment trial is held by the legislature -- therefore without a jury. However, the legislators could be considered a jury of the president's peers.

http://en.wikipedia.org/wiki/Impeachment_in_the_United_States

I believe that murder trials must have a jury.