Harold Hongju Koh is Martin R. Flug '55 Professor of International Law at Yale University, from which he is on leave to serve as Legal Adviser to the United States Department of State. He began teaching at Yale Law School in 1985 and served from 2004 until 2009 as its fifteenth Dean. He has argued before the United States Supreme Court and he has testified before the U.S. Congress more than twenty times.  While he is considered a liberal in international law and U.S. constitutional law, he is also acknowledged as a legal teacher and thinker across the ideological spectrum: the very conservative John Yoo, in the introduction to a 2005 book, wrote "Harold Koh sparked my interest in foreign affairs and the Constitution;" Yoo often quotes Koh as an authority on the other side of Yoo's argument.
He has Republican supporters, including former Solicitor General Ted Olson, for whom he worked in the Justice Department, and Judge Malcolm Richard Wilkey of the United States Court of Appeals for the District of Columbia Circuit, for whom he was a law clerk. 
On June 25, 2009, the U.S. Senate confirmed Professor Koh, after considerable controversy and political maneuvering. Opponents claimed that his views on transnationalism meant that he wanted to subordinate the sovereignty of the United States to international organizations, and make foreign court decisions binding on U.S. judicial decisions. John Fonte of the Hudson Institute, writing in National Review, quotes a 2004 article by Koh, in The American Prospect about the transnational system:
Transnational legal process encompasses the interactions of public and private actors — nation states, corporations, international organizations, and non-governmental organizations — in a variety of forums, to make, interpret, enforce, and ultimately internalize rules of international law. In my view, it is the key to understanding why nations obey international law. Under this view, those seeking to create and embed certain human rights principles into international and domestic law should trigger transnational interactions, which generate legal interpretations, which can in turn be internalized into the domestic law of even resistant nation-states.
Fonte did not include Koh's words immediately before the quote:
Fonte goes on to say this transnational process affects U.S. courts and legislation, but never states that Koh believes that it should be controlling, while Koh actually suggested its preemptive use by the U.S. Fonte suggests such unelected interests would be a strong influence, and thus undemocratic. Not all domestic interest groups are elected, however, and still influence the U.S. process. For example, Concerned Women for America, an interest group, strongly opposed Koh's nomination; they oppose any international body having any authority over the United States, and oppose the ratification of treaties.  Supporters say that this is a visceral and untrue response to anyone who would undo the unilateralism of the George W. Bush Administration. Koh's perspective on international courts, in the above American Prospect article not quoted by Fonte, was
Yet for more than half a century, the United States has promoted international criminal adjudication as being in our long-run national interest. This policy has stemmed from a sensible prediction that, on balance, the United States is far more likely to act as a plaintiff than as a defendant before these tribunals, and thus has much more to gain than to lose from their effective functioning...Our support for the Yugoslav tribunal helped the United States avoid sending troops to Belgrade to seize and oust Milosevic.
One specific accusation, by former George W. Bush Administration speechwriter and current managing editor of National Affairs Meghan Clyne in a New York Post , was that at a 2007 dinner of the Greenwich Yale Club, according to lawyer Steven Stein, says that, in addressing the Yale Club of Greenwich in 2007, Koh claimed that "in an appropriate case, he didn't see any reason why sharia law would not be applied to govern a case in the United States.". Clyne also wrote, "Worse, the State job might be a launching pad for a Supreme Court nomination. (He's on many liberals' short lists for the high court.) Since this job requires Senate confirmation, it's certainly a useful trial run."
The organizer of the event at which he was alleged to have made this statement wrote
I was the organizer of the Yale Club of Greenwich event on March 13, which Meghan Clyne references.
The account given by Steve Stein of Dean Koh's comments is totally fictitious and inaccurate. I was in the room with my husband and several fellow alumni, and we are all adamant that Koh never said or suggested that sharia law could be used to govern cases in US courts.
The subject of his talk was Globalization and Yale Law School, so, of course, other forms of law were mentioned. But never did Koh state or suggest that other forms of law should govern or dictate the American legal system. 
His confirmation hearing was in April. "To the disappointment of his excitable critics, Koh has never suggested the subordination of the American legal system to foreign powers. He has championed respect for our obligations under treaties to which the U.S. has explicitly signed. He views international legal sources as a valid--but not binding--source of inspiration and perspective for U.S. courts.The use of such nonbinding sources to bolster legal arguments is a central and uncontroversial tenet of the American judicial process: Law review articles and other academic sources are a lynchpin of the opinions of courts everywhere; current Chief Justice John Roberts has even cited a Bob Dylan song." 
From 1998 to 2001, he served as U.S. Assistant Secretary of State for Democracy, Human Rights and Labor, and previously had served on the Secretary of State's Advisory Committee on Public International Law.
He has been awarded eleven honorary doctorates and three law school medals and has received more than thirty awards for his human rights work.
He is recipient of the 2005 Louis B. Sohn Award from the American Bar Association International Law Section and the 2003 Wolfgang Friedmann Award from Columbia Law School for his lifetime achievements in International Law.
Before joining Yale, he practiced law at Covington and Burling from 1982-83 and at the Office of Legal Counsel at the Department of Justice from 1983-85.
In 1993, he led a legal action to shut down the first U.S. detention camp, then for Haitian refugees, at Naval Station Guantanamo Bay. Koh sued both the George H. W. Bush Bill Clinton administrations to establish the principle that Guantanamo is not a law-free zone.
He is a Fellow of the American Academy of Arts and Sciences and the American Philosophical Society, an Honorary Fellow of Magdalen College, Oxford, a former Visiting Fellow at All Souls College, Oxford, and a member of the Council of the American Law Institute. He is a member of the Boards of Directors of the Brookings Institution, Human Rights First, the American Arbitration Association, and the National Democratic Institute.
He is recipient of the 2005 Louis B. Sohn Award from the American Bar Association International Law Section and the 2003 Wolfgang Friedmann Award from Columbia Law School for his lifetime achievements in International Law. He has been named one of America's “45 Leading Public Sector Lawyers Under The Age of 45” by American Lawyer magazine and one of the “100 Most Influential Asian-Americans of the 1990s” by A magazine.
- B.A. degree from Harvard College
- B.A. and M.A. degrees from Oxford University, where he was a Marshall Scholar
- J.D. from Harvard Law School, where he was Developments Editor of the Harvard Law Review served as a *law clerk for Justice Harry Blackmun of the Supreme Court of the United States and Judge Malcolm Richard Wilkey of the United States Court of Appeals for the District of Columbia Circuit.
- Harold Hongju Koh, Yale Law School, Yale University
- John Yoo (2005), The Powers of War and Peace: the Constitution and Foreign Affairs since 9/11, University of Chicago, ISBN 0226960315, p. xi
- Brandt Goldstein (1 April 2009), "Confirm Harold Koh as State Department Legal Adviser", Huffington Post
- John Fonte (28 April 2009), "Koh Fails the Democracy Test: Consent of the governed? Or rule by international wisemen?", National Review
- Harold Hongju Koh (20 September 2004), "On America's Double Standard: The good and bad faces of exceptionalism.", American Prospect
- Senate Vote Threatens American Sovereignty: Concerned Women for America Urges Senate to Oppose Harold Koh, Concerned Women for America, 24 June 2009
- Dahlia Lithwick (3 April 2009), "And Then They Came for Koh...If mainstream America can't stand up for Harold Koh, we will get precisely the government lawyers we deserve.", Slate
- Meghan Clyne (30 March 2009), "Obama's Most Perilous Legal Pick", New York Post
- Robin Reeves Zorthian (1 April 2009), "Caught Offguard by Koh: Another Odd Obama Pick", New York Post
- Ronan Farrow (28 April 2009), "Commentary: Confirm Harold Koh", Forbes