President Trump 'wants to take down' special counsel Mueller: Top House Democrat

“The president wants to take down Bob Mueller," Schiff said.

"The question is why," Schiff continued. “I think the answer is they want to lay the foundation to discredit whatever Bob Mueller comes up with. They’re essentially engaging in a scorched-earth litigation strategy that is beginning with trying to discredit the prosecutor.”

Schiff was responding to a question from Raddatz on whether Trump’s defenders are right to raise concerns that lawyers hired by Mueller have contributed to Democratic political candidates.

“Anyone who knows Bob Mueller knows he is choosing the best people to serve on this investigative team -- people that have experience in the issues that he wants to investigate and believes need to be investigated,” Schiff said.

President Trump has repeatedly expressed frustration with the Russia investigation, including saying on Twitter on Thursday that the probe is “the single greatest WITCH HUNT in American political history - led by some very bad and conflicted people!”

Rosenstein has privately discussed with colleagues the possibility of rescusal, as ABC News has reported.