Solus Christus is the teaching that Christ is the only mediator between God and man, and that there is salvation through no other.
This position was taken to contrast what reformers were seeing in the Catholic church of the time. They were rejecting the idea that they had to go through the Pope or a Priest to be at peace with God.
So what to Catholics believe today?
"480 Jesus Christ is true God and true man, in the unity of his divine person; for this reason he is the one and only mediator between God and men."Or read this article: http://www.newadvent.org/cathen/10118a.htm
So do protestants still need to protest this one?
Yes, they still have priests and the pope, but most Protestant churches also have Pastors and denominational presidents and boards which may play similar roles. There is a tendency to view the Pastor as the authority, leader or head of a local church. Denomination government structures may also step in to give additional authority and control. Is this really that different today than what we see in the Catholic Church?
So today there is another movement that I think has a similar call to that of the reformers.
Is it OK for this new movement to insist that Christ alone is the head of the church?
Can we join with the reformers and say "Solo Christo!"?