Top Dem doesn't expect to see 'evidence' of Trump wiretap claims

Rep. Schiff also suggested that the claims damage Trump's credibility.

Either way, Schiff said the wiretapping claim has damaged Trump’s credibility and could have “real world consequences” in the future.

"We're going to be able to ask the director of the FBI among others, is there any truth of this? Have they seen any evidence of this? They would be in a position to have to know. And I think on March 20th, if not before, we'll be able to put this to rest," he said. “But I don't think anyone really has any question about this, George. The only question is why the president would make up such a thing.”

“I have been very critical of the FBI and their willingness to cooperate in the investigation. I can say that that substantially changed,” Schiff said.

“I wouldn't want to reach a conclusion at the outset of our investigation as to whether we're going to be able to demonstrate collusion,” Schiff said on “This Week.” “Maybe we will, and maybe we won't. Maybe it existed, and maybe it didn't. But I do think it's our obligation to do everything possible in as nonpartisan a basis as possible to answer those very important questions. And I wouldn't start out by concluding one way or the other.”

“We follow that evidence where it leads, and not leap to any conclusions on the front end,” Schiff added.

Schiff also responded to concerns from fellow Democrats that they will not be able to conduct a complete investigation, saying partisan politics could limit the investigation.“To be honest, George, I don't know whether we'll be able to conduct this to its completion, whether we'll have the kind of bipartisan cooperation that we need,” Schiff told Stephanopoulos.

“I think it's clear it's in the national interests to try,” Schiff added. “And if we get to the point where we can't, I think it's our obligation in the opposition to speak out and say this is not legitimate. We are being walled off from certain areas of investigation. But I think we owe it to the country to try, that's certainly my intention.”