U.S. Sen. John Thune said the picture emerging of President Donald Trump's interactions with Ukraine is "not a good one."

Thune told reporters on Wednesday that he had concerns the lack of transparency in the closed-door testimony could affect the credibility of the impeachment process, but the testimony by Bill Taylor, the U.S. ambassador to Ukraine, could hurt Trump. Taylor testified on Tuesday that Trump's allies made clear to Ukraine that military aid would be contingent on whether it investigated an energy company that employed the son of Democratic presidential candidate Joe Biden.

"The picture coming out of it based on the reporting we've seen is, yeah, I would say it's not a good one," Thune said. "But I would say also, until we have a process that allows for everybody to see this with full transparency, it's pretty hard to come to hard and fast conclusions."

Meanwhile on Wednesday, about a couple dozen Republican House members stormed in protest the House Democrats' closed-door testimony of Laura Cooper, the deputy assistant secretary of Defense for Russia, Ukraine and Eurasia.

U.S. Rep. Dusty Johnson said he wasn't among the group of Republicans and he heard about it after leaving a committee hearing, but he supports the Republicans' actions.

"I'm seriously concerned about the lack of transparency and that people have been denied access to basic information that has been historically made available to members. They want to hear what these witnesses are saying. It doesn't seem out of line to me," Johnson said during a media call on Wednesday.

More:GOP protest halts House Democratic impeachment deposition of Defense official Laura Cooper

He said protections for the president and access for House members have been typically provided and those are being denied. He said those deficiencies need to be rectified if the House wants to have a process that'll have meaning.

Johnson voted to censure House Intelligence Chair Adam Schiff in a House resolution that was defeated in a 218-185 vote on Monday.

The censure vote is "key evidence" of Republicans' frustrations with "procedural deficiencies in the impeachment inquiry," Johnson said. No matter South Dakotans' opinions about the impeachment inquiry, they should be concerned about the work that's not getting done in Congress while it's going on, he added.

"We want to have a process that Americans can believe in. Americans are not going to believe in a process that is not open, sound and fair. Congress has some work to do on that front," Johnson said.

Johnson noted that there were closed-door meetings before hearings began in previous impeachment attempts, but he said House Speaker Nancy Pelosi "triggered" a constitutional process when she announced the impeachment inquiry and therefore the process should be open.

"I think this is a serious and severe departure from historic norms," Johnson said.

U.S. Sen. Mike Rounds didn't return a request for comment.