Following a week of public impeachment hearings in the House Intelligence Committee, renowned public broadcast journalist Bill Moyers on Friday expressed alarm at President Donald Trump's attacks on the witnesses who came forward to inform the public about the president's misconduct in office—and the complicity of top administration officials.

"For President Trump to vigorously denigrate them, to malign them, with [Trump's personal attorney Rudy] Giuliani leading a smear campaign against these fine public servants, is disgusting, it's repulsive, it's abominable," Moyers said in an interview with MSNBC's Chris Hayes late Friday.

As Common Dreams reported, Trump tweeted attacks on former U.S. Ambassador to Ukraine Marie Yovanovitch as she testified last Friday, sparking accusations of "witness intimidation in real time."

In a lengthy "Fox & Friends" interview Friday, Trump accused David Holmes, political counselor to the top American diplomat in Ukraine, of fabricating a phone call between Trump and U.S. Ambassador to the European Union Gordon Sondland. The president went on to say he "hardly" knew Sondland, who donated $1 million to Trump's inaugural committee in 2017.

Watch Moyers' MSNBC interview:

Moyers, whose public broadcast career began with PBS in the 1970s, has witnessed and covered impeachment proceedings against three presidents—Richard Nixon, Bill Clinton, and now Donald Trump.

In partnership with his long-time collaborator and Common Dreams senior writing fellow Michael Winship, Moyers launched a campaign earlier this month urging PBS to carry the Trump impeachment hearings live and re-air them in primetime, as the network did with the Nixon hearings.

While noting that there are differences between the current impeachment proceedings and those of the past—Nixon "never admitted his crimes," Moyers pointed out, and "Trump announced his in public"—the legendary journalist told Hayes Friday that there are also significant similarities.

"Republicans did not rush to get rid of Nixon," Moyers said. "That's basically where the Republican Party is today. Partisanship is a great insurance policy against impeachment. If the Republican Party members don't fold, don't see the light, go to the other side, vote against Trump, I doubt that there will be an impeachment."

"If Republicans hang tough... if they cling to their false defense of the president, ignoring the evidence with their lies," added Moyers, "it's going to be a long, drawn-out fight."