Updated at 11:15 a.m. with additional information.

WASHINGTON — A senior North Texas Republican on Thursday came to the defense of embattled Environmental Protection Agency administrator Scott Pruitt, saying the Cabinet member is "not the first person to be the victim of ... Washington politics."

Rep. Joe Barton, R-Ennis, offered that cover as Pruitt testified on Capitol Hill amid ongoing controversy over allegations of excessive spending and ethical mishaps.

The Texan suggested that Pruitt was an easy target for Democrats because of his policy positions, such as "fighting some of the Obama administration radical clean air policies." He explained that if "you can't debate policies in Washington, you attack the personality."

"That's what happening to you," Barton told Pruitt, adding later that the EPA chief's penchant for flying first class "may look bad, but it's not illegal."

Barton, who is retiring this year amid scandal over lewd photos he sent in an extramarital affair, is no stranger to taking those kinds of stands. He gained notoriety in 2010, for instance, by apologizing to BP for the White House's tough response to the Deepwater Horizon disaster.

1 / 4Environmental Protection Agency Administrator Scott Pruitt testifies before the House Energy and Commerce subcommittee hearing on Capitol Hill on April 26, 2018.(Pablo Martinez Monsivais / The Associated Press) 2 / 4EPA Administrator Scott Pruitt and EPA CFO Holly Greaves prepare to testify before the House Energy and Commerce Committee's Environment Subcommittee on April 26, 2018. The focus of nearly a dozen federal inquiries into his travel expenses, security practices and other issues, Pruitt testified about his agency's fiscal year 2019 budget proposal.(Chip Somodevilla / Getty Images) 3 / 4Scott Pruitt and CFO Holly Greaves arrive to testify.(Chip Somodevilla / Getty Images) 4 / 4Protesters hold up signs and shirts behind EPA Administrator Scott Pruitt, accompanied by Holly Greaves, EPA chief financial officer.(Alex Brandon / The Associated Press)

But Pruitt has presented a challenging case for Republicans, particularly since the White House reportedly considers the EPA chief to be on thin ice despite liking his deregulatory agenda.

Among the growing list of controversies surrounding Pruitt: pricey air travel at taxpayer expense. An expansive security operation. A condo rental from a Washington lobbyist. Installation of a $43,000 soundproof phone booth at Pruitt's EPA office.

Pruitt, citing a "learning curve," told the House Energy and Commerce Committee that he has to "take responsibility to make changes to the agency." But he also said that "a lie doesn't become true just because it appears on the front page of the newspaper."

"Those who have attacked the EPA and attacked me are doing so because they want to derail the president's agenda," he said. "I'm not going to let that happen."

Some Republicans, such as Rep. John Shimkus of Illinois, urged Pruitt to offer his "side of the story on the rumors and allegations you're facing." Others, including the other Texans on the committee, either ignored the ethical questions or nodded at them only in passing.

"The solution is between you and President Donald Trump," said Rep. Pete Olson, R-Sugar Land. "You work at his pleasure, and it's that pure and simple."

Democrats, however, were not so forgiving.

Rep. Frank Pallone, D-N.J., said Pruitt was "unfit to hold public office" and "undeserving of the public trust." Rep. Paul Tonko, D-N.Y., said the EPA boss has "failed as a steward of American taxpayer dollars and of the environment." And others drilled in on the allegations.

"I'm not doing this to hassle you. I'm doing this as an elected official," said Rep. Diana DeGette, D-Colo. "Everything we do has to be to the highest ethical standards."