Five years ago, Ukraine’s Maidan uprising ousted President Viktor Yanukovych, to the cheers and support of the West. Politicians and analysts in the United States and Europe not only celebrated the uprising as a triumph of democracy, but denied reports of Maidan’s ultranationalism, smearing those who warned about the dark side of the uprising as Moscow puppets and useful idiots. Freedom was on the march in Ukraine. Today, increasing reports of far-right violence, ultranationalism, and erosion of basic freedoms are giving the lie to the West’s initial euphoria. There are neo-Nazi pogroms against the Roma, rampant attacks on feminists and...