Yoo's visit in particular has provoked a strong and thoughtful discourse about the legal positions he took in memos he wrote after the 9/11 attacks, while in the Office of Legal Counsel at the Department of Justice. Some ask whether he should have been offered a visiting professorship.
In my view, the legal positions Yoo advanced in the post-9/11 memos are supported -- some well supported; others at least arguable -- by constitutional text, historical understanding and legal precedent. In fact, many of those positions were shared by Clinton administration officials now serving in the Obama administration.
For example, one memo argued that the Geneva Convention does not apply to unlawful combatants, such as members of Al Qaeda, who target civilian populations and otherwise violate the rules of war. That position was shared at the time by Eric H. Holder Jr., now the U.S. attorney general. In 2002, in a CNN interview, Holder stated: "It seems to me that given the way in which they have conducted themselves, however, that they are not, in fact, people entitled to the protection of the Geneva Convention. They are not prisoners of war."
Another controversial legal position advanced in the memos was that provisions of the Bill of Rights did not apply beyond the shores of the United States, particularly to wartime conduct. For authority, the memo cited the case of Harbury vs. Deutch, in which a three-judge panel of the D.C. Circuit Court of Appeals held in 2000 that the 5th Amendment does not apply abroad to claims of torture by CIA-paid agents against foreign nationals.
At issue were allegations of torture that occurred over an 18-month period -- half of it during the first year of the Clinton administration and that, according to the complaint, included this: "They chained and bound him naked to a bed, beat and threatened him, and encased him in a fullbody cast to prevent escape."
The appeals court accepted the arguments made by Wilma Lewis, a U.S. attorney during the Clinton administration, that the 5th Amendment does not apply to claims of torture involving "an alien rebel commander leading an attempt violently to overthrow a foreign government," even when the torture was alleged to have been committed by paid agents of, and at the request or at least full knowledge of, the CIA. The opinion was written by Judge David S. Tatel, a Clinton appointee, and joined by Judge Harry T. Edwards, a Carter appointee, and Judge Douglas H. Ginsburg, a Reagan appointee.
Even the controversy about the 4th Amendment in the most recently released memo is not as clear-cut as Yoo's opponents would have it. The 1972 Supreme Court decision they rely on in their arguments indeed held that the 4th Amendment requires a warrant for electronic surveillance of U.S. citizens in domestic security matters. But the opinion for the court by Justice Lewis F. Powell expressly left open the question of whether those requirements would apply to domestic surveillance of agents of foreign powers. Powell strongly suggested that they would not, favorably citing a District Court decision that drew such a distinction because the Supreme Court had long recognized the president's "inherent power with respect to foreign relations."
In other words, whether the 4th Amendment limited the president's commander-in-chief power to conduct surveillance of enemy agents on our soil, in time of war, was a close enough question that the Supreme Court had not resolved it. Yoo's position was therefore hardly incompetent and indefensible, as some of his detractors claim. Indeed, it would be incompetent and indefensible for Yoo to have ignored Powell's caveat and concluded that the case resolved a question the court explicitly left open.
After 9/11, the lawyers at the Justice Department faced unprecedented legal questions. They had been given the task of identifying the executive powers that could legally be brought to bear to prevent future attacks. That they were aggressive in their legal interpretations should come as no surprise, given the circumstances.
In the end, the president's options were more thoroughly vetted by lawyers than at any wartime era in our nation's history. There were no wholesale detentions based on race, such as occurred under President Roosevelt in World War II. No systematic suppression of antiwar speech, such as under President Wilson in World War I.
That there is a great deal of disagreement about the constitutionality of the lines the lawyers drew is also no surprise -- the Constitution deliberately keeps the lines between congressional and executive wartime powers, and between those branches and the courts, deliberately ambiguous. But disagreement about closely contested issues hardly supports the exaggerated claims that Yoo and his colleagues shredded the Constitution, or that he should not be teaching law.
John C. Eastman is dean at Chapman University School of Law and a professor of constitutional law.