Shinpei was a radical government liberal, and he is known for the Ministry of Justice law no. 22 (prostitute liberation law) which was also called the livestock liberation law, as well as the Ministry of Justice law no. 46 which recognized administrative litigation for the people.
政府内における急進的な民権論者であり「牛馬ニ物ノ返弁ヲ求ムルノ理ナシ」として牛馬解放令とも呼ばれた司法省達第二十二号（娼妓解放令）、民衆に行政訴訟を認めた司法省達第四十六号などが知られる。