If I am not mistaken, water baptism is one of the 7 sacraments and it can be performed by laymen and must not necessarily involve clergy. In such a case, since Protestants have no apostolic succession unlike the Orthodox, are their baptisms valid in their own right?
To be clear, belief in the Holy Trinity is a prerequisit that seems obvious and mainline Protestants do believe in the Holy Trinity. Some of the Reformers had a similar view of Catholics being their brothers by baptism, notably John Calvin.
EDIT : My question is different to certain others because it deals with the validity of the sacrement of baptism in Protestant circles instead of merely if God will have extraordinary mercy on Protestants as opposed to ordinary mercy with sacrements. If the mercy is extraordinary it almost pushes salvation in Protestantism to the level of salvation in for instance paganism, where there are no elements of the Church to draw life from like a source of water. However if Protestantism has ordinary significance then we can safely say that Protestants are Christians, and not simply hope that they are.