WASHINGTON -- U.S. Sen. David Perdue does not have a good taste in his mouth after the first day of the impeachment trial, a 12-hour slog that consisted of several unsuccessful attempts by Democrats to introduce new witnesses and evidence.

House Democrats serving as impeachment managers said they wanted to ensure they were able to present a full case against President Donald Trump, who faces removal from office. But Perdue said he went home feeling frustrated by how Democrats framed their efforts.

“They came over last night and lectured us about fairness and due process and I was offended by that personally,” he said during an afternoon break. “They called the president’s team liars and called us complicit in a cover-up.”

Perdue and other Senate Republicans have criticized how the House carried out its impeachment investigation. It started with a closed-doors investigation, and Trump didn’t get an opportunity to defend himself until the inquiry shifted to the Judiciary Committee.

Trump and his lawyers declined that invitation.

Democrats say that was his opportunity to defend himself against charges he abused the power of his office and Trump declined. They have described Republican criticism of the process as an attempt to deflect attention away from Trump’s alleged wrongdoing.

Perdue said Democrats are asking the Senate for a level of treatment they refused to grant the president.

“Hypocrisy,” he said. “I’ll just come out and say that: hypocrisy.”

These disagreements played out during Tuesday’s session, and as the night wore on both sides began to use stronger language toward the other.

Chief Justice John Roberts even paused the proceeding around midnight to “admonish both the House managers and the president's counsel in equal to terms.”

“I do believe those who are addressing the Senate should remember where they are,” he said.