A key ally of President Donald Trump is dismissing the latest developments in the impeachment investigation, calling it a "bunch of B.S."

Sen. Lindsey Graham told reporters Tuesday he doesn't plan to read the transcripts Democrats are releasing from the impeachment investigation, despite demanding that they be made public. He says he's "written the whole process off."

The South Carolina Republican is also downplaying revised testimony from Gordon Sondland, the U.S. ambassador to the European Union, about the Trump administration's pressure on Ukraine.

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Sondland for the first time acknowledged a potential quid pro quo with Ukraine, with American military aid held up as the administration pushed the country to release a statement about fighting corruption.

Graham says, "that's his opinion," adding, "I don't think the president did anything wrong.

Graham said he also agrees with Sen. Rand Paul, R-Ky., that the identity of the whistleblower whose concerns led to the inquiry be revealed.

"Well, the whistleblower statute was never meant to give you anonymity. It was meant to allow you to come forward without being fired. You can't use anonymity in a criminal process,"  Graham said. "You can't use anonymity in a civil process. And you shouldn't be able to. This is a misuse of the statute. We need to know who this person is, because, without the complaint, there would be no impeachment inquiry."

Although there has now been first-hand testimony from people who reportedly heard the July 25 phone call between Trump and Ukrainian president Volodymyr Zelensky and corroborated what was discussed, Graham said the whistleblower complaint itself should not have been enough to launch the inquiry.

"You can't prosecute somebody based on a whistleblower complaint because every defendant has a right to confront their accuser. Nor should you be able to impeach any President in the United States -- Republican or Democrat based on an anonymous allegation," Graham said.