The only Republican witness testifying in the impeachment hearing before the House Judiciary Committee on Wednesday is an expert on constitutional law and a frequent critic of the House impeachment inquiry.

Jonathan Turley also has a dog, and as he told the committee in his opening statement, that dog is angry.

"I get it. You are mad. The president is mad. My Republican friends are mad. My Democratic friends are mad. My wife is mad. My kids are mad. Even my dog seems mad, and 'Luna' is a goldendoodle and they don't get mad," he testified.

"We are all mad. Where has that taken us? Will a slipshod impeachment make us less mad or will it only give an invitation for the madness to follow in every future administration? That is why this is wrong."

Turley, one of four witnesses to testify in the hearing on "Constitutional Grounds for Presidential Impeachment," was the only Republican witness allowed by Democrats. He complained about the partisanship on display at the hearing — something that was highlighted in his initial questioning.

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Turley was only asked one question by Democrats in their first 45 minutes of questioning, and was the only witness questioned by Republicans during their first 45 minutes of question.

He differed with the other experts who testified, saying he doesn't think Democrats have enough evidence that Trump committed bribery in his dealings with Ukraine, and the "record does not establish obstruction in this case." He urged Democrats to do a more thorough investigation. "Fast is not good for impeachment," he said.

The law professor took a more aggressive position on impeachment when he testified before House Judiciary during impeachment proceedings against Bill Clinton in 1998. In his testimony then, he urged the House to move forward with impeachment even if thought the Senate might not remove him.

"There is a considerable difference between the House refusing to impeach a president over serious conduct and the Senate refusing to remove a president for such conduct. The House decision establishes the expectations of a people in the conduct of the Chief Executive and serves as a critical deterrent to presidential misconduct," he testified at that time. “While the Senate can decide not to remove a president in the interests of the nation for a variety of reasons, the House should not falter in maintaining a bright line for presidential conduct."

The professor has done work for House Republicans in the past.

Turley, who got his law degree from Northwestern University, represented then-House Speaker John Boehner and House Republicans in a lawsuit against then-President Barack Obama, and has appeared as a legal commentator on NBC and MSNBC.

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He also once represented workers who'd been injured while working at the secret military base Area 51 in Nevada. He's currently the J.B. and Maurice C. Shapiro Professor of Public Interest Law at George Washington University Law School.

His testimony about his dog struck a chord on social media, where it inspired a parody Twitter account named "Jonathan Turley's Goldendoodle." "My name is Luna and I'm pissed," the page's bio reads.

Luna has appeared on social media before — Turley tweeted out a picture of her with his class last month.

Professor Luna Teaches Animal Liability At GW Law https://t.co/zJ2JSnNmWo pic.twitter.com/88fnxw2lim — Jonathan Turley (@JonathanTurley) November 5, 2019

"Professor Luna teaches animal liability at GW Law," the tweet read.

"The students did not seem to mind that the Professor would occasionally doze in front of class," he wrote in a blog post.