I think it would be pretty much the same reaction John Calvin and John Knox would have if they were around to see what is happening in the United Presbyterian Church USA and the same reaction Charles and John Wesley and John Whitfield would have if they were around to see what is happening in the United Methodist Church...they would all be sickened, disgusted and outraged at what is happening.
These churches are supported largely by estates that were willed to them back when they stood for Christ.
I think often of the good Methodists, et al, who left money in their wills to keep supporting the evangelical work of these churches. How they would be horrified to find that their gift had been turned against God's work!