Professor Campbell, who wrote widely in legal, political and moral philosophy (especially on rights and human rights), taught for more than twenty years in Scotland, at the Universities of Glasgow and Stirling, before joining the Australian National University law faculty in 1990.  He retired in 2001, and was at the time of his death an emeritus Professorial Fellow at the Charles Stuart University.  I will add links to memorial notices as they appear.

(Thanks to Matt Kramer and Brian Bix for alering me to his passing.)