Asaho Mizushima is a professor at Waseda University School of Law, who specializes in areas such as constitutional law, theory of legal policy, and peace studies. Before he joined the Waseda faculty in 1996, he was an associate professor at Sapporo Shōka University, the later-Sapporo Gakuin University, and at Hiroshima University. He received his LLM (1978) and PhD (1997) from Waseda University.

Claiming the Abe administration’s decision to reinterpret the constitution to enable Japan to exercise its collective self-defense would violate the constitution, he opposed the 2015 security bills (2015 essay). Mizushima organized the Association of Scholars Opposed to the Security-related Laws (安全保障関連法に反対する学者の会) and Rikken Demokurashī no Kai (立憲デモクラシーの会) with other scholars.

Mizushima supports and publicizes messages about maintaining the present "pacifist constitution" on his website. In addition to posting weekly online articles, he also offers unique perspectives on constitutional revision, introductions to his books, and many links to both foreign and domestic websites dealing with the postwar constitution.