R.C. Sproul has written a few words to explain why he did not sign the Manhattan Declaration, and you may find those words here. On the other end of the spectrum, Al Mohler has explained in this place why he did sign it.
I am with Sproul when it comes to his statement that he would be "happy to march" with RCs and EOs to protest the slaughter of the unborn, and I am also with him in saying that he could not consent to do so on the basis of a "unified understanding of the gospel." As I have written before, I would not have signed that document while, with Sproul, I can certainly applaud the three central themes of the document -- the God-given dignity of all human life, the meaning of marriage, and the nature of religious liberty.
In short, I would not have signed (with Sproul) while I could have signed (with Mohler). My reasons for refraining were strategic and rhetorical and not doctrinal per se, as I explained before. More on this in a moment.
I appreciated Sproul's observation of the tendency toward "studied ambiguity" in these sorts of statements. And if I may be allowed to point it out, it is an ambiguity that was not apparent when it comes to the definitions of human life, heterosexual marriage, or freedom of conscience. There is wiggle room on terms like gospel, or Christian, and there is no similar wiggle room on a word like marriage.
Now the reason I wrote before that a classical Protestant could sign this thing without specific doctrinal compromise is that wiggle room is the kind of thing that you can wiggle in. You can understand the terms as you understand them, and no one is requiring you to understand them differently. Mohler is right about that. There is no specific theological compromise involved at that point, although there is confusion and muddle down the road (whihc is my point), when you try to explain to a parishioner why he shouldn't partake of the Mass at his nephew's wedding. "But you . . ." "But I thought . . ."
At the same time, if you, like Ligon Duncan, have made a special point out of not letting other Reformed Christians (like, say, me, ferinstance) use the term Christian in two different ways, then it is a bit thick to start using it yourself in those same two different ways. And so I believe it is fully appropriate for someone like Sproul to call him on it. When I use the term in these two senses, I spend a lot of time explaining exactly what I mean by it (in order to give PCA study commissions something to ignore in their footnotes). When Lig Duncan assumes those same distinctions without explanation, it seems to me that somebody is overegging the pudding.
Since I have just spoken of two different ways of using the word Christian, what are those ways? In brief, for those just joining us, a Christian is someone who, because he has heard the gospel of God proclaimed, has subsequently believed in Christ through that gospel in his heart, and has been converted to God. That's a Christian, the kind that is going to Heaven when he dies. A Christian is also someone who has been baptized in the triune name and who is consequently not a Buddhist.
Incidentally, I also appreciated and agreed with this statement from Sproul: "I believe there are true and sincere Christians within the Roman Catholic and the Orthodox churches. But these people are Christians [first sense!] in spite of their church’s official doctrinal positions." Amen to that. But they are Christians in the second sense also.
Now what could interupt this feast of reason and flow of soul? I do want to offer some criticism of Sproul in all this, and I hope to do so in the same spirit that Calvin displayed in responding to Luther, when some of that man's greatness overflowed onto the floor.
"It is only in our united proclamation of the one, true gospel of Jesus Christ that any heart, any mind, or any nation will truly change, by God’s sovereign grace and for His glory alone."
Threats to "united proclamation" come from two directions. One is to make the terms of the one, true gospel broader than God has made them, which is what Sproul had in view, and the other error is to make them narrower than God has made them. It is not sufficient to say no to a broad, ecumenical latitudinarianism -- we must also say no to a truncated and blinkered sectarianism.
In this instance, Sproul avoided both errors. He said what he believed, and he said it without writing off fellow Reformed men who shared with him his understanding of the gospel, but who differed with him at this specific point.
"The Manhattan Declaration puts evangelical Christians in a tight spot. I have dear friends in the ministry who have signed this document, and my soul plummeted when I saw their names. I think my friends were misled and that they made a mistake, and I want to carefully assert that I have spoken with some of them personally about their error and have expressed my hope that they will remove their signatures from this document. Nevertheless, I remain in fellowship with them at this time and believe they are men of integrity who affirm the biblical gospel and the biblical doctrines articulated in the Protestant Reformation."
This is a model of Christian charity in the midst of strong disagreement. It is the way this kind of thing ought to be done -- but it is not the way the PCA handled the FV controversy. And when Sproul spoke to that particular issue on the floor of GA, he was painting the side of the barn with a broad roller brush, and not with the miniaturist care he displayed here.
And this is why the point is important -- please believe that I am not bringing up a grudge, or some old score to settle. I respect and admire Sproul. But when you exclude men who share with you a commitment to the historic Reformed faith, and then something like this Manhattan Declaration comes up, you really are in the position of the boy who cried wolf. The PCA is riddled with men who are skilled at playing politics, and when you play politcs for long enough, and have accused enough five-sola men of being closet Romanists, you are then kind of stuck when Lig Duncan leaves a case of boxed fruit like this on your doorstep. This kind of thing leaves plenty of room for the outside cynical observer to conclude "it's all politics, man."
But it isn't all politics. The gospel, long term, really is at stake. But it is just as threatened by incompetent heresy hunters who can't read as it is by fuzzy muzzy group heresy huggers who can't think.