Interior Secretary Ryan Zinke responded to U.S. Rep. Raul Grijalva's call Friday for him to resign with a tweet calling the Democrat a drunk who has wasted taxpayer dollars trying to cover it up.

For Zinke, who pledged on his first day in office to hold Interior officials and staff to the highest ethical standards, the tweet also seemed counter to the moral character expectations the U.S. Navy has for Seals. The secretary frequently points to his days as a Seal.

Congressman Grijalva, who is expected to assume the chair of the House Natural Resources Committee in January and as such will have investigative authority over Secretary Zinke and actions he has taken, was brief in his reaction to the tweet.

“The American people know who I’m here to serve, and they know in whose interests I’m acting. They don’t know the same about Secretary Zinke," said the Democrat.

Spurring Zinke to castigate Rep. Grijalva was the congressman's op-ed piece in USA Today on Friday that called on the Interior secretary to resign.

While the secretary continues to project confidence, questions have grown since the election about his future plans, and the White House reportedly fears that he would be unable to withstand scrutiny on Capitol Hill. Those fears are justified. Mr. Zinke has never even tried to offer an explanation for the sheer scope of his well-documented scandals.

This silence is insulting to the American people, and given the Nov. 6 election results it is unsustainable. [. . .]

The American people need an Interior Department focused on addressing climate change, enhancing public recreation, protecting endangered species and upholding the sovereign rights of Native American communities. These are not matters of personal preference – they are enshrined in law and supported by voters. The department needs someone accountable at the helm who believes in this mission.

Mr. Zinke is not that person. Federal agencies cannot function without credible leadership, and he offers none. He needs to resign.

Zinke spokeswoman Heather Swift did not respond Friday to an inquiry about the secretary's tweet.

The secretary's tweet did not provide context for his allegations, but a Washington Times story from November 2017 claimed Grivalja arranged a $48,395 payoff to a former staffer who claimed he was often drunk in his office and that led to a hostile work environment. The congressman has denied the allegations, and in an op-ed piece that ran on Tuscon.com he wrote that "I do not work while drunk and have never had a hostile workplace environment."

Rep. Grijalva added that a non-disclosure agreement has prevented him from discussing the alleged settlement in more detail.

Secretary Zinke has been under scrutiny practically since the day he was sworn in. Critics have said he is too close to the energy industry that can profit from public lands exploration on- and offshore.

The secretary was heavy criticized for his role in President Trump's decision to shrink Grand Staircase-Escalante and Bears Ears national monuments in Utah by a combined 2 million acres. While Interior's Office of Inspector General recently cleared Secretary Zinke of any wrongdoing in how the redrawn boundaries of Grand Staircase-Escalante moved a prominent Utah politician's property out of the monument, several other investigations in the secretary's actions continue.

One of those pending investigations is looking into whether the Interior Department blocked a casino deal in Connecticut, while another regards conversations Zinke had with then-Halliburton Chairman David Lesar about a development project in Zinke's hometown of Whitefish, Montana.