Beetz's areas of expertise were the civil law of Quebec, and Canadian constitutional law. Because his time on the Supreme Court coincided with major federal-provincial disputes on federalism issues, he took part in several major federalism decisions. More than anyone else on the Court at the time, he supported the provinces in the division of powers, taking the traditional Quebec interpretation for a decentralised federation. Since Chief Justice Laskin was a strong centralist, they usually took opposing views on federalism issues. James MacPherson, former Dean of Osgoode Hall Law School, has summarised the Beetz-Laskin debates: "The result was that constitutional lawyers, academics, and students were regularly treated to two scholarly, beautifully reasoned, and eloquent — but in the end — opposing judgments. Put simply, Professors Laskin and Beetz, as Chief Justice and Justice, elevated the level of discourse in Canadian constitutional law."