re: #111 Belafon
As mistermix points out at balloon-juice.com, the Senate gets to make its own rules, and could set up rules to be allowed to vote on any testimony. So, Roberts could say yes, and then the majority of the Senate says nope.
Entirely possible, but it still puts Republicans in the Senate in the position to have to overrule the Chief Justice of the Supreme Court on a question of law… to protect an unpopular president charged with actual crimes in an election year.