Why did Richardson and Ruckelshaus resign during the Watergate "Saturday Night Massacre", rather than simply refuse?

Question

On October 20 1973 President Nixon ordered Attorney General Elliot Richardson to fire special prosecutor Archibald Cox, who was investigating the Watergate scandal. Richardson refused and handed in his resignation. Nixon then ordered Deputy Attorney General William Ruckelshaus to fire Cox, who also refused and resigned. Cox was eventually fired by Robert Bork. This event is known as the "Saturday Night Massacre".

Both men resigned as they believed that firing Cox was illegal, something which was confirmed through the courts just a few weeks later. The entire event later became a major reason for Nixon's impeachment procedure, which would almost certainly have lead to a conviction if Nixon had not resigned and been granted a pardon by Gerald Ford.

My question is: why did they resign, rather than saying "no, this is clearly illegal and I cannot comply"? It seems to me that handing in your resignation when asked to commit illegal acts is a rather curious course of action?

Answer 1

It was necessary to maintain the independence of the Special Prosecutor.

Fortunately, Attorney General Richardson's resignation letter is easily searchable on Google. In his letter, he explains that he made several commitments and pledges not to interfere with the work of a Special Prosecutor. When Nixon demanded he fire the Special Prosecutor, that would be interfering with the work of the Special Prosecutor, which directly conflicted with those commitments and pledges. There was simply no way to follow his commitments to both his boss the President and the American people. So he quit.

Dear Mr. President:

It is with deep regret that I have been obliged to conclude that circumstances leave me no alternative to the submission of my resignation as Attorney General of the United States.

At the time you appointed me, you gave me the authority to name a special prosecutor if I should consider it appropriate. A few days before my confirmation hearing began, I announced that I would, if confirmed, "appoint a special prosecutor and give him all the independence, authority, and staff support needed to carry out the tasks entrusted to him." I added, "Although he will be in the Department of Justice and report to me--and only to me--he will be aware that his ultimate accountability is to the American people."

At many points throughout the nomination hearings, I reaffirmed my intention to assure the independence of the special prosecutor, and in my statement of his duties and responsibilities, I specified that he would have "full authority" for "determining whether or not to contest the assertion of 'Executive Privilege' or any other testimonial privilege." And while the special prosecutor can be removed from Office for "extraordinary improprieties," I also pledged that "The Attorney General will not countermand or interfere with the Special Prosecutor's decisions or actions."

While I fully respect the reasons that have led you to conclude that the Special Prosecutor must be discharged, I trust that you understand that I could not in the light of these firm and repeated commitments carry out your direction that this be done. In the circumstances, therefore, I feel that I have no choice but to resign.

In leaving your Administration, I take with me lasting gratitude for the opportunities you have given me to serve under your leadership in a number of important posts. It has been a privilege to share in your efforts to make the structure of world peace more stable and the structure of our own government more responsive. I believe profoundly in the rightness and importance of those efforts, and I trust that they will meet with increasing success in the remaining years of your Presidency.

Respectfully, ELLIOT L. RICHARDSON

Though I was unable to find Deputy Attorney General Ruckelshaus' resignation letter, it is not a stretch to assume the reasoning is the same.

Answer 2

It Sounded Better

The attorney general (AG) is an appointed position whose occupant serves at the pleasure of the president (POTUS, for some reason). AGs and similar officeholders will sometimes use a threatened resignation as a way to underline the complete unacceptibility of a proposed course of action. (See here and here for 2 examples that have leaked from the Trump administration.) American politics has been sharply partisan for most of its history: A threatened resignation from within the administration blows up POTUS's ability to claim all of the other side's objections are just self-serving bickering and nonsense. (Almost always the strongest play, especially for people like Nixon who are essentially elected by their base as 'our sonnuvabitch'.) Even if the person resigning is a nobody, once it goes public it becomes clear that this actually is A Thing that even people from the president's side see as unacceptible.

If they didn't resign, they could be fired, in this case by a president who made himself synonymous with 'Dirty Tricks'. Even if they were to go public afterwards, which would burn professional bridges inside the party they've already tied themselves to for decades, they (a) come across much more starkly as sore losers and (b) are at the mercy of whatever counterstory Nixon's team would've offered for why they'd 'actually' deserved to be fired.

Once it becomes completely clear that POTUS can't be talked out of an immoral order, the AG has no better move than to resign. It keeps their narrative clear, allows a self-effacing but forceful letter to be composed and freely shared, provides maximum political pressure against the administration's action, and keeps the AG's options open for their future career both within and outside the party. Simply refusing to comply and waiting until some excuse is made up to justify termination doesn't solve anything and creates lots of further problems. Barricading yourself inside your office and refusing to recognize POTUS's authority to remove you... well, the US may be on its way there after the last 4 years but it hasn't happened yet as far as I know...