exercised "poor judgment", he did not find "professional misconduct" sufficient to authorize OPR "to refer its findings to the state bar disciplinary authorities". Yoo contended that the OPR had shown "rank bias and sheer incompetence", intended to "smear my reputation", and that Margolis "completely rejected its recommendations". Although stopping short of referral to the bar, Margolis had also written: [Yoo's and Bybee's] memoranda represent an unfortunate chapter in the history of the Office of Legal Counsel. While I have declined to adopt OPR's findings of misconduct, I fear that John Yoo's loyalty to his own ideology and convictions clouded his view of his obligation to his client and led him to author opinions which reflected his own extreme, although sincerely held, views of executive power while speaking for an institutional client. Margolis's decision not to refer Yoo to the bar for discipline was criticized by numerous commentators. Publications Yoo's writings and areas of interest have fallen into three broad areas: American foreign relations; the Constitution's separation of powers and federalism; and international law. In foreign relations, Yoo has argued that the original understanding of the Constitution gives the President the authority to use armed force abroad without congressional authorization, subject to Congress's power of the purse; that treaties do not generally have domestic legal force without implementing legislation; and that courts are functionally ill-suited to intervene in foreign policy disputes between the President and Congress. With the separation of powers, Yoo has argued that each branch of government has the authority to interpret the Constitution for itself. In international law, Yoo has written that the rules governing the use of force must be understood to allow nations to engage in armed intervention to end humanitarian disasters, rebuild failed states, and stop terrorism and the proliferation of weapons of mass destruction. Yoo's academic work includes his analysis of the history of judicial review in the U.S. Constitution. Yoo's book, The Powers of War and Peace: The Constitution and Foreign Affairs after 9/11, was praised in an Op-Ed in The Washington Times, written by Nicholas J. Xenakis, an assistant editor at The National Interest. It was quoted by Senator Joe Biden during the Senate hearings for then-U.S. Supreme Court nominee Samuel Alito, as Biden "pressed Alito to denounce John Yoo's controversial defense of presidential initiative in taking the nation to war". Yoo is known as an opponent of the Chemical Weapons Convention.