Senate Judiciary Committee Chair Chuck Grassley (R-IA), asked Rosenstein if he had any reason to believe that he could not handle an investigation from which Sessions had recused himself.
"Senator, I'm not aware of any," Rosenstein replied before explaining that he is not familiar enough with the current situation at DOJ to make a determination about recusal from a probe into Russian election interference.
"I don't know what, if any investigation is currently ongoing within the department. So if I were confirmed, I would need to familiarize myself with the facts, I would need to consult with experts in the department. We have a complex set of rules and statutes that govern recusals," he said. "And so I'm not aware of any requirement for me to recuse at this time, but as a lawyer, Senator, I would have to know what it is I'm recusing from."
Asked again by Grassley how he would decide when a special prosecutor would be appropriate, Rosenstein said it would be his job to make sure that any investigation would be carried out independently.
Sen. Dianne Feinstein (D-CA), the committee's ranking Democrat, later returned to the question of special counsel and asked Rosenstein if he would support one. In response, Rosenstein noted that the current acting deputy attorney general, Dana Boente, has not appointed any special prosecutor and explained that he was not in a position to "overrule" that decision.
Feinstein tried to clarify again whether the nominee supported appointing a special prosecutor.
"I’m simply not in a position to answer the question because I don't know the information that they know, the folks that are in the position to make that decision," Rosenstein replied.
Sen. Pat Leahy (D-VT) brought up the subject again in his questioning, prompting Rosenstein to offer that he was willing to appoint a special counsel "whenever I determine it is appropriate based upon the policies and procedures of the Justice Department."
Sen. Richard Blumenthal (D-CT), who has threatened to delay Rosenstein's confirmation if he does not commit to appointing a special prosecutor, also quizzed the nominee on the matter.
Rosenstein told Blumenthal that he "should not be promising to take action on a particular case" before being confirmed to the post.
Rosenstein said at the top of the hearing in response to Grassley that he was not aware of any contact he'd had with Russian officials, and that he had not discussed the topic of presidential campaigns communicating with Russia with Sessions.
This post has been updated.