The distinction between sacrament and ordinance, it would seem to me, is the direction of the act: a sacrament is when God empowers through the action, while in an ordinance, God responds to the action.
If Baptism is an ordinance, then it would of necessity have to be a conscious choice of the baptized, since otherwise there would be nothing to which God could respond. In that case, the Baptists and their fellow travelers would be correct: baptism would have to be an act of a person who has chosen to repent and believe the Gospel.
If Baptism is a sacrament, however, then it would have to be the conscious act of the baptizer, since God would be working through the act. In other words, the baptizer would engage in an act which s/he clearly intends to be a baptism (as opposed to, say, a shower, or diving), and an infant, who is incapable of repentance, would thereby obtain God's grace and sanctification based on the faith of the parent (cf. Acts 16:33).
That would not necessarily mean, however, that the baptizer would have to grasp the totality of what God was doing in order for the sacrament to occur, since God does not need us to understand His actions in order to act.
So if baptism is a sacrament, and Rev. Baptistminister thinks it is an ordinance, God's action in the sacrament would be no less, because God is not constricted by our misunderstanding of His actions--for which we can thank Him, since all of us misunderstand His actions some of the time.
And I would take it one step further, though it is off the topic here. If the Real Presence of Christ is in the bread and wine of communion, then it is there, regardless of whether the institutor and/or the partaker believe it to be there. When I receive communion from my LCMS pastor, he and I believe that the Presence is there. That Rev. Baptistminister does not accept the Presence in communion is of no account: God is not limited by our lack of understanding, for which I thank Him, since I am sure I have a lack of understanding of most, if not all, of what He does. What "saves" Rev. Baptistminister is that he, when he institutes communion in his church's worship, does not desecrate the elements, but treats them with respect--he may not follow the divine liturgy or use a chalice pall, but his (mis?)understanding of communion as an ordinance leads him to act in ways that demonstrate his willingness to meet God there, and God shows Himself in ways that would surprise the minister, were he to truly understand them.
An interesting point of view.
How do you reconcile the view of a sacrament, when God empowers through the action with the definition: An efficacious sign of grace, instituted by Christ and entrusted to the Church, by which divine life is dispensed to us through the work of the Holy Spirit
Also, can you clarify what you mean, God responds to the action when speaking of an "ordinance?"
So if baptism is a sacrament, and Rev. Baptistminister thinks it is an ordinance, God's action in the sacrament would be no less, because God is not constricted by our misunderstanding of His actions--for which we can thank Him, since all of us misunderstand His actions some of the time.
First, let me point out that the Catholic Church accepts as valid any baptism that is done using a Trinitarian formula ("I baptize you in the name of the Father, the Son, and the Holy Spirit"...as opposed to "Creator, Savior, Sanctifier" or some other variant) and that uses water as matter. I accept the ruling.
However, the Code of Canon Law states, Can 832 §2. Those baptized in a non-Catholic ecclesial community must not be baptized conditionally unless, after an examination of the matter and the form of the words used in the conferral of baptism and a consideration of the intention of the baptized adult and the minister of the baptism, a serious reason exists to doubt the validity of the baptism. Frankly, although I accept the Church's decision on the matter, I linger with the question if the intent of a "ordinance" type baptism (either that of the baptizer or the baptized) is the same as the intent of those doing a "sacramental" baptism. The comments in this thread, frankly, reinforce that questioning.
Frankly, I wonder if those who practice "ordinance" baptism subscribe to the line from the Nicene-Constantinopalitan Creed that says I acknowledge one Baptism for the remission of sins.