Phi Alpha Delta (ΦΑΔ or PAD) is the largest co-ed professional law fraternity in the United States. Phi Alpha Delta has members who are university students, law school students, lawyers, judges, and politicians. It was founded in 1902 and today has over 300,000 initiated members. Approximately one out of six attorneys in the United States is a member of PAD.
Five of the sitting Justices of the United States Supreme Court are members of PAD including: Ruth Bader Ginsberg (1993–present), Stephen G. Breyer (1994–present), Samuel A. Alito, Jr.(2006–present), Sonia Sotomayor (2009–present), and Elenda Kagan (2010–present). United States Vice President, Joe Biden is also a member of PAD (2009-2017).