Sen. Bob Corker (R-TN) on Wednesday morning called for congressional investigations into Michael Flynn and the Trump administration’s ties to Russia, warning that failure to address the issue could “destabilize” the federal government’s ability to enact policy.

“The base issue is getting to the bottom of what the Russian interference was and what the relationship was with associates of the Trump effort, and so that is the big elephant in the room that has got to be dealt with in the most appropriate way,” Corker said on MSNBC’s “Morning Joe.”

“There’s the issue of: Is the White House going to have the ability to stabilize itself? This affects us not just with international issues that are brewing all around the world — all kinds of problems — but the domestic agenda here,” Corker continued.

The senator said that investigating leaks to the press about the White House, which some Republicans have focused on, is a “sub-issue.”

“The big issue right now is dealing with this Russia issue, making sure that it doesn’t destabilize our ability to move ahead as a country and deal with important issues,” he said.

Flynn resigned from his role as national security adviser following reports that he spoke with the Russian ambassador about U.S. sanctions before Trump’s inauguration. The White House and President Donald Trump had reportedly been warned about the content of the calls a couple weeks before Flynn resigned, but Vice President was left in the dark until late last week. Following Flynn’s resignation, multiple outlets reported that additional Trump aides were in contact with Russian officials before the election.

Corker told MSNBC on Wednesday that he’s concerned about Trump’s past comments praising Putin. He said that the Trump administration has evolved on several foreign policy issues, but that they have not changed their stance toward Russia.

“The one area where the evolution is not taking place is with Russia. Russia is not our friend,” he said. “This relationship that seems to exist and seems to be preeminent and seems to be driving so much of the conversation within the White House, to me, is still not righted itself.”

Corker seemed hopeful that the administration will change its view, but said that there are still concerns about Trump’s policy toward Russia.

“People are concerned that he is going to strip away sanctions that are in place. I think that is almost impossible now with everything that’s happened, but that is the one area that is hard to understand,” he said.

He also said that he hopes Congress will be able to question Michael Flynn, but he said that such an effort may not be possible if the FBI is still investigating. Corker indicated that speaking with Flynn would help Congress determine what the White House knew about his efforts.

“I don’t know that I want to get into the intrigue of the daily blows, but I want to understand what’s happened here,” Corker said. “If I were them, by the way, if I were the people leading the Trump effort at the White House, I would want to make sure, with all of the suspicion, that everybody fully understood what has taken place, otherwise maybe there’s a problem that obviously goes much deeper than what we now suspect.”