Methodism & Christian Nationalism

What is "Christian Nationalism" and how should Methodists think about it? Arkansas United Methodist Bishop Gary Mueller recently commented to the Arkansas Democrat Gazette about United Methodism's split: "There are parts of the church in which traditional Trinitarian thinking is beginning to morph into Unitarian thought. However, there are also parts of the church where I am concerned that traditional Christian orthodox thought is beginning to resemble white Christian nationalism."