WASHINGTON, D.C - The first phase of President Donald Trump's impeachment trial is underway in the U.S. Senate. Alex Cameron is following trial from our new Washington Bureau. He spoke to Senators Jim Inhofe and Senator James Lankford just before things got started Tuesday, January 21.

There has been a buzz here on Capitol Hill since I first got here early Tuesday morning - media everywhere, citizen protesters, and the stars of the show - the Senators themselves. I was fortunate to get a word with each of ours.

Walking over to the Capitol for the start of the first day's session, Senator James Lankford acknowledged the gravity of the moment.

"It's certain a moment in history that we're walking through," Senator Lankford said.

Both Senator Lankford and Senator Inhofe have said on the record they don't think the President's done anything to warrant removal from office. So as jurors now, I asked if they could have an open mind.

"Well my mindset - I'm going to have to hear something I haven't heard before," said Senator Jim Inhofe.

Inhofe said he's not interested in hearing from witnesses who aren't already part of the House's case.

"We heard that over the weekend, and I thought it was very weak," he said. "I didn't think it was anything new, and I don't think that's appropriate, so the answer would be no."

Senator Lankford doesn't rule out allowing witnesses to testify. He understands what he and his colleagues do will set a precedent.

"We're too early to be able to say what that would be now," he said. "The entire country is talking about this, but there are only 100 people in the country that get a chance to actually vote on it, to resolve it, and I understand the significance of being one of those 100 people."

On a side note, we reported that Senator Inhofe was not here last Thursday when the 99 other Senators were sworn in. We were told it was due to a family medical issue.

He told me today his wife of 60 years, Kay, had a stroke last week. Senator Inhofe tells me she's in therapy and improving nicely.