Say what you will about Peter Leithart, but when it comes to his theology, the man just plain ol' doesn't care about anything other than that it is biblical.
Is this a bad thing?
When the study committee which he and I petitioned the Northwest Presbytery of the PCA to form began its work, Leithart's only request was that, in addition to comparing his views to the Westminster Standards, we also take the time to engage his work from the vantage point of Scripture. It was obvious that this latter concern far outweighed the former in his mind.
The conclusions of the minority report that I authored were that Leithart's positions, though biblically defensible to a certain degree, were nonetheless clearly contrary to the system of doctrine found in our Confession and Catechisms. The problem, the minority argued, was that he failed (or was unwilling) to read the Bible through the lens of the doctrinal standards of the PCA. And Leithart's response, in a nutshell, was "Isn't being biblical enough?"
Hence the complex nature of Reformed confessionalism. On the one hand, we recognize that there is no "view from nowhere," and that we simply cannot read Scripture in a lens-less, objective, Cartesian way. All of us bring presuppositions to the interpretive table. On the other hand, though, we don't want to be accused of simply reducing the Bible to the confession's handmaiden, as if Scripture is merely a collection of prooftexts to buttress one's own systematic theology.
An example from Leithart's own views would be the fact that Paul says in Romans 6:7 that the baptized believer has been "justified from sin." Clearly, Leithart argues, the word "justify" is being used as a kind of synonym for "sanctify," and not to denote God's one-time declarative act of pardon and imputation of alien righteousness. Our understanding of the term "justification," therefore, ought to be broad enough to include this usage, as well as the OT's usage of tsadaq in contexts were the issue is deliverance from enemies, not forensic acquittal.
I admit, I can see Leithart's point and can understand his frustration at being told "No, you must not echo Paul's language since it contradicts our theology." But at the same time, is there not a place for being a team-player and being willing to employ terminology that tries to avoid confusing people unnecessarily?
The options, as I see them, are as follows: confessional denominations like the PCA can either (1) broaden our theological parameters to make room for someone who can make a case that his theology is biblically plausible, or (2) we can insist that our ministers at times must avoid speaking the Bible's language for fear of muddying the systematic waters.
And I must say, I'm not completely thrilled about either of those choices (but then, who ever said being confessional would be easy?).