In a civil and (certainly) criminal context, the Defendant’s presence at trial is mandatory. This rule is about ensuring fairness to the Defendant, most of all.
And as a defense lawyer, I would be a fool not to force my client to attend the entire trial to watch exactly what was said by the opposing lawyer and every witness, so that my client can be prepared for what might happen when he or she is called to the stand.
It is also about showing to the jury that my client is a real person who cares about the case, and will be affected by the jury’s decision one way or the other.
After digging for about 5 minutes, I’m not finding any information about whether prior U.S. presidents who were also impeached attended their own Senate trials, or for how long.
I do know for a fact that Clinton at least testified in a deposition. Trump hasn’t even done that.
So, no, I’m not smoking a crack pipe. But thanks for that latest round of ad hominem insults.