The Ukraine phone call transcript is slowly convincing the public to have an open mind about the Trump impeachment inquiry, former Clinton adviser Richard Goodstein said Thursday.

It does not matter if the whistleblower is a Republican, a Democrat or unaffiliated, their report should be taken seriously, Goodstein said on "Tucker Carlson Tonight."

"It's the president's words," he said of the transcript of President Trump's call with Ukrainian President Volodymyr Zelensky from earlier this year.

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"Whether the whistleblower is an 'R' or a 'D' or came from Mars, or whatever they blew the whistle about -- we see this so-called transcript... so damning that the public increasingly with each passing week is more and more inclined to say, 'Yeah, actually, I think you should be impeached.' "

In response, host Tucker Carlson challenged Goodstein, saying he is simply playing politics ahead of the 2020 U.S. presidential election.

"There's an election in a year and you don't like Trump," Carlson said. "That is the referendum. It is a democracy."

Goodstein countered that partisanship may have ruled during the Clinton impeachment.

"That'd be true if it were [about] having sex with an intern," Goodstein said, "but he is trying to get China and Ukraine and Russia to make sure that we don't have a fair election," he said of Trump.

He added that House Speaker Nancy Pelosi, D-Calif., struck the right tone when she repeatedly told journalists she was "praying for" Trump amid the impeachment inquiry turmoil.

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"You never heard a soul on the Republican side feel any sense of remorse for going after [former President Bill Clinton] and trying to kick him out of office -- talk about a coup -- because he had sex and didn't want to talk about it on the record."

"You never heard a soul on the Republican side feel any sense of remorse for going after [former President Bill Clinton] and trying to kick him out of office -- talk about a coup -- because he had sex and didn't want to talk about it on the record." — Richard Goodstein, former Clinton adviser

Earlier Thursday, former U.S. envoy for Ukraine Kurt Volker appeared on Capitol Hill as one of the first witnesses to go before a congressional body amid the Trump impeachment inquiry triggered by the whistleblower complaint about Trump's July 25 phone call.

Volker was participating in a closed-door transcribed interview with members of the House Intelligence, Oversight and Foreign Affairs committees after the complaint mentioned him as having allegedly played a role in Trump lawyer Rudy Giuliani’s investigations connected to Ukraine. Volker resigned soon after the complaint was made public last week.

Fox News' Ronn Blitzer and Mike Emanuel contributed to this report.