Doug Chaplin is asking for a “good argument” for the North Galatian hypothesis from someone who advocates it. I’ll give it a shot.
The North Galatian hypothesis is preferable on the basis of a sound dating of the letter. If we agree that after the Jerusalem conference (Gal 2:1-10 ~ Acts 15, though issues pertaining to the apostolic decree are either unhistorical or happened later, like at Acts 18:23) and Antioch incident (Gal 2:1-14) Paul went to the region of Phrygia and Galatia (as reported in Acts 16:6 (which distinguishes these regions from the “South Galatian” places he just visited), and later wrote to the Galatians in between the writing of I & II Corinthians (Mark Goodacre makes a persuasive case for this), then the theory works fine and makes perfect sense.
The South Galatian hypothesis derives from an agenda to save Luke’s testimony and chronology as much as possible (for instance by equating Gal 2:1-10 with Acts 11:27-30 rather than Acts 15) and thus downward dating Galatians as early as possible. I once flirted with this scheme in my early years on Corpus Paulinum, but quickly abandoned it. There are problems with confining Paul’s activity to the regions of Syria and Cilicia for a 14-year period (prior to the conference, as Luke would have it), followed by Herculean accomplishments across Greece and Asia Minor during the closing years. Luke, in any case, certainly doesn’t refer to the southern regions in Acts 13-14 as “Galatia”.
Our conclusions must depend on how we reconstruct Pauline chronology more generally, since nothing in Galatians specifies what region Paul really has in mind. This is how I see events unfolding:
Second Jerusalem visit (agreement on the collection and to exempt Gentiles from circumcision)
Antioch Incident (pillars revoke their decision to exempt Gentiles from circumcision)
In (North) Galatia (collection begun there)
Writing of I Corinthians (directions given for the collection there)
Crisis in Galatia (lapse of collection there)
Writing of Galatians
Crisis in Corinth (lapse of collection there)
Writing of II Corinthians (more than one letter?)
Crisis in Rome
Writing of Romans
Third Jerusalem visit (presumed delivery of the collection, though not from the Galatians)
Galatians has always been a difficult letter to date, but once we appreciate that Paul failed in Galatia everything falls into place. Esler sensed that Paul failed based on dramatic argumentative shifts in Romans, and Goodacre confirmed it based on an analysis of the Corinthian letters. I think they’re both right — Goodacre in particular that Galatians was written between I & II Corinthians. There’s just no need to postulate “South Galatia” as the region for Paul’s addressees.
UPDATE: Doug Chaplin responds, claiming the North Galatian hypothesis is too speculative. I find this amusing since the South originated only because certain scholars wanted to correlate everything Paul says with everything Luke says. But in any case, I don’t buy Doug’s treatment of Acts 16:6, where Luke is obviously referring to the northern tribal area. He also claims that “ethnic Galatia seems a little too far off the beaten track” given Paul’s usual itinerary, but as Esler and others have pointed out, both Paul and Luke vaguley account for this. Paul says that he came to Galatia because of a “weakness in the flesh” (Gal 4:13). Luke says that he travelled through the tribal region “having been prevented by the Holy Spirit from preaching the word in Asia” — in other words, barred from continuing westward along the Cilician Road. I have no idea why Paul would have left the road and headed north to Galatia on account of an illness of the eyes. Maybe he just wanted to escape the urban scene for a while?