He has been a Fellow of Wolfson College in the University of Cambridge since 2002 and has taught international law at that University as well as in visiting capacity at the Catholic University of Lille and University of St. Gallen. He has held visiting fellowships at the Max Planck Institute for Public International Law in Heidelberg, the Hoover Institute at Stanford, and the National Security Institute at George Mason University. He is author of eight books and over a hundred articles in academic and policy journals, as well as a contributor to news outlets including the Wall Street Journal, The Hill, The Federalist, and National Review. His most recent book, Nuclear Arms Control in Peril: Why the Nuclear Non-Proliferation Treaty Matters and How to Save It (December 2024), makes a conservative case for nuclear arms control. He graduated from Harvard College (summa cum laude, Phi Beta Kappa Junior Twelve), the Yale Law School, and the University of Cambridge, where he earned a PhD on a Fulbright Scholarship. He clerked on the U.S. Court of Appeals for the 1st Circuit after law school. He was born in Gettysburg, Pennsylvania and attended public schools, K through 12, in North Attleborough, Massachusetts.