Robert Mueller is trying to be careful and keeping his answers as close to the report as possible, according to two sources who are close to him.
Some of the questioners are using rapid-fire or long-winded questions to try to have him depart from the report’s language.
Republicans in particular have used their time to try to impeach the witness.
The Mueller style to try to keep it dry and not provide fodder for the ongoing political fights doesn’t do well in this kind of hearing.
A congressional source involved in negotiations surrounding Mueller’s appearance says that Mueller’s team told the committees that he would decline to read from his report during the hearing.