A number of law professors have signed an open letter to the President’s counsel asserting that the President is bound by a duty of good faith in carrying out executive functions. 

Here is the basic claim (footnote omitted):

First, the best understanding of Article II of the Constitution is that presidential actions motivated by self-protection, self-dealing, or an intent to corrupt or suborn the legal system are unauthorized by and contrary to Article II of the Constitution. Second, and even if one does not accept the foregoing construction of Article II, Congress has enacted obstruction of justice statutes that prohibit any person from acting “corruptly” to interfere with federal criminal investigations. Whatever a President may have been able to do in the absence of such statutes, Congress’s judgment that obstruction of justice is prohibited binds the President.

I will have some comments on the substance (in Part 2, forthcoming) but to begin I want to highlight the methodology:  This is an originalist letter.  In the section discussing the Constitution, almost the entirety of the argument invokes the text as it was originally understood, the intentions of the framers (“Founders”), and the English law background of the Constitution.  Here is the letter’s substantive argument in full (footnotes omitted, but they do not contain material additional arguments, only sources), with my notes after each paragraph:

While Article II empowers the President to execute the laws, it also constrains him in so doing. The “Take Care Clause” requires that the President “shall take Care that the Laws be faithfully executed” (emphasis added). Article II contains a mandatory Oath of Office whereby the President must swear to “faithfully execute the office of President.” Like the Take Care Clause, the Oath also conceives of the President’s role as a duty—to “preserve, protect, and defend the Constitution”—not a personal power.

(This paragraph is a pure textualist argument.)

When the Founders thus defined the Presidency as an office bound and restricted by overarching duties of care and faithfulness (fidelity) to the Constitution and laws of the United States, they were invoking the well-known concept of treating a public officer as a fiduciary. In the eighteenth century, as today, English and American law required fiduciaries to act always with due care, solely for the good of their beneficiaries, and to abstain from self-dealing, corruption, and other kinds of self-interested actions.

(This paragraph relies on the eighteenth century concept of a fiduciary and uses that concept as evidence of how the “Founders” [it’s unclear if this means the drafters/ratifiers or more broadly the founding generation] understood the words and structure of the Constitution.  That’s conventional originalist argumentation.  I don’t understand the reference to the meaning of fiduciary “[i]n the eighteenth century, as today” to detract from the originalism of the argument.  Rather, it’s saying that the eighteenth-century meaning hasn’t changed, so it should be easy for us to understand.  Justice Scalia commonly used this expression.)

The President’s duties of care and faithfulness are the fiduciary duties most explicitly required by the Constitution, a document that refers to many offices as “Offices of Trust,” invoking the legal concept of trusteeship (a fiduciary relationship). Mirroring the Constitution’s text, th