Editor's Note: (Julian Zelizer is a history and public affairs professor at Princeton University, editor of "The Presidency of Barack Obama: A First Historical Assessment" and co-host of the "Politics & Polls" podcast. Follow him on Twitter: @julianzelizer. The opinions expressed in this commentary are his own.)
(CNN) EPA Administrator Scott Pruitt finally resigned. The decision does not come as much of a surprise to anyone who has been following the news. The only real question is why it took so long to happen.
Over his 18-month tenure, Pruitt, who was an anti-environmental warrior for the right, amassed a long record of ethically questionable practices and was facing over a dozen separate investigations. In the history books, he will likely go down as a poster child for Cabinet officials who didn't believe that conflicts of interest matter and who were willing to use their office for material gain.
Pruitt's alleged wrongdoing draws attention to an issue at the heart of the Trump administration: ethical corruption. Pruitt's problems comported with a White House that seems to mock concerns about good government, and the idea that public officials work first and foremost to serve the public interest and not for personal gain.
The tone was established when President Donald Trump did not create a strong and clear firewall between his own global business and the presidency. He left the sprawling family business -- the Trump Organization -- in the hands of his two sons and did very little to provide real assurances that his own actions, such as frequent, taxpayer-funded trips to Trump resorts, would not undermine the need to make sure that public officials act for the good of the country.
That's said, Pruitt is but one example of the ethics crisis. Housing and Urban Development Secretary Ben Carson had to defend the purchase of a $31,000 dining set for his office, while Department of Interior Secretary Ryan Zinke insisted he was not involved with the decision to grant a $300 million contract to a tiny company from his hometown to help with the recovery in Puerto Rico.
Then there was former Secretary of Health and Human Services Tom Price, who had to resign when the public learned of his traveling on expensive private jets and military aircraft. And who can ignore the numerous questions about the conflict of interest between the businesses of Ivanka Trump and Jared Kushner and the important roles they play in the White House?
But nobody in the administration, other than Trump, came to embody the ethics crisis facing the White House more than Pruitt. The EPA administrator would travel on private and military planes, instead of commercial airlines, when going home to Oklahoma. He allegedly had his staff undertake all sorts of personal requests, which included trying to find a job for his wife with the Republican Attorneys General Association, and exploring a business opportunity for her at Chick-fil-A. And, according to The Washington Post, one staffer had to go out looking for lotion that Pruitt wanted from Ritz Carlton hotels.
Meanwhile, his relationship with lobbyists was as shady as could be. Reporters discovered that Pruitt rented an apartment, at an extremely low rate, that was owned by a health care lobbyist whose husband was also a lobbyist who had worked on EPA-related issues. Another lobbyist arranged a December trip to Morocco.
Even Pruitt's resignation letter reflects the influence of the Trump presidency. Just as Trump never apologizes, Pruitt didn't either. Instead, he blamed his resignation on the "unrelating attacks" he and his family had endured.
The administration will certainly try to separate itself from Pruitt's scandals by either continuing to dismiss them as "fake news" or claiming they have nothing to do with the President. But Pruitt must be seen in the context of the Trump presidency. This is a President who has not taken ethics seriously and has no problem pushing the boundaries of what kinds of actions are permissible when public officials use their authority for personal gain.
In a White House that has been one continuous advertisement for the Trump name, it is not surprising that someone like Pruitt was allowed to serve for so long.
The biggest issue right now is not what happens next to Pruitt, but will the Republican Congress continue to live with the kinds of blurred ethical lines that have become normalized under Trump. Based on the past year and a half, the safe bet is probably yes.