Because it's not relevant to the case against this particular defendant.
Sussman is being charged with lying to the FBI. A Twitter post from Hillary Clinton that makes no reference to Sussman doesn't seem to be evidence of anything that isn't already known.
So why do you think Durham wants to introduce it as evidence? He must have a motive for doing.
Sussman’s lawyers are trying to use the Rules of Evidence to stem the flow of incriminating evidence into the case. The Obama-appointed judge seems to have heard the “dog whistle” and is acting accordingly.
You seem to have all the answers. Can you tell me why this Sussman character is not being charged with conspiracy? Durham is basically claiming he passed fabricated evidence and intentionally misled the fbi/doj to initiate an investigation of Trump.
I think the point that Durham was trying to make with the Clinton tweet was that the tweet proves that she had knowledge of the materials that Sussman, Elias, FusionGPS, and Perkins Coie were manufacturing.
Clinton knowing about the hoax materials would be proof that Sussman was engaged in work for the Clinton campaign, which would prove the lie that Sussman wasn't doing work "for any client."
Durham was intending to juxtapose this with the attempts by Elias and Perkins Coie to have their documents client-attorney excluded as protected work product. That would only be possible if they were working on behalf of a client. Marc Elias was already trapped into that argument and tried to backpedal his prior comments about providing legal services for a client.
-PJ
A Twitter post from Hillary Clinton that makes use of the fruit of Sussman's lie tends to corroborate that Sussman was working for Clinton or her campaign.
already known? In a trial, nothing whatever is known unless it is admitted in evidence.