Phil Johnson's discussion and definitions of fundamentalists and evangelicals is interesting (see here). I think the problem that arises with some (maybe, many) fundamentalists is that they don't stick to his definition. He repeats the phrase "essential truth of the gospel" ... and I'd love to know what this includes. Surely his doctrine of salvation and theology proper include this. However, what about an issue like psychology ... those who are integrationists and (versus?) those who are nouthetic/biblical counselors? Is that really an "essential turth of the gospel"? Would Johnson refuse to ally with someone over this issue?
I'm sure some fundy's would boil it down to the sufficiency of Scripture. But can anyone really go so far as to say that learning some listening techniques from Rogerian therapy is denying an "essential truth of the gospel"!
Conclusion: if fundy's stuck to his definition, they'd be okay; but they keep making non-essentials the cause of division ... which is explicitly against his definition. (If you don't know who Phil Johnson is see here; if you've never seen his site on good/bad theology on the web ... go here.)