When I wrote The Next Christen­dom back in 2002, I was quite proud of the wide range of global churches and Christian traditions that I covered. I did not notice a curious omission in my index: no mention of Baptists. The absence provoked one exasperated Bap­tist colleague to complain, semiseriously, “We spent how much on foreign missions last year, and this is what we get?” That gap was not intended as a slight or insult on my part, but it does point to a curious aspect of the modern Baptist tradition.

Fifty or a hundred years ago, Christian denominations were heavily concentrated in Europe or North America. Since that time, those bodies have expanded worldwide to the point that Global South believers now predominate, and they usually aspire to make their distinctive voices heard. Name any major Protestant tradition, and that is more or less its modern history. Baptists represent the conspicuous exception to this rule. As in previous generations, Baptists remain heavily concentrated in one Global North region, namely the United States, where they still constitute the largest Protes­tant tradition.

Estimates of the number of Baptists worldwide vary enormously—far more widely than for most churches. Guesstimates for the total of believers range anywhere from 50 to 110 million, taking all theological shades together. The most accurate figure lies in the lower part of that range.

Whatever the overall totals, what’s striking is the continuing size of the U.S. proportion. The largest 40 or so Baptist groups when combined ac­count for around 55 million people, 40 million of whom adhere to bodies in the United States. That compares with 7 million members in Africa, 5 million in Asia, and 2 million in Latin America. Non-U.S. numbers rise if smaller denominations are included, but they count their numbers not in the millions but in the tens of thousands, and applying the same standard also raises U.S. figures comparably.

Of the six largest denominations, by far the most significant are U.S. groups such as the Southern Baptist Con­vention and the major African-American networks. The only overseas body to approach this elite category is the Nigerian Baptist Conven­tion, which has about as many members as the Baptist Gen­eral Convention of Texas.

The relative global numbers are counterintuitive for Americans, who naturally re­gard Baptists as a very significant part of the Christian spectrum. Outside the United States, though, Baptists are quite a marginal presence. Africa’s 10 million Baptists are a tiny proportion of a continental Christian total ap­proaching half a billion. Out of Brazil’s 45 million Protes­tants, just 2 million are Baptists.

That continuing distribution of believers between Global North and South is ironic given Baptists’ fervent commitment to foreign missions and the achievement of so many legendary evangelists and teachers. In some areas, especially in India and South Asia, Baptist missionary advances have been very marked. And mere numbers say nothing about the nature of faith or the quality of practice. Global South Baptists have played key roles in political life, and especially in education. Even so, the fact remains: Baptists differ from virtually all other Christian traditions in that newer churches are nowhere near matching or overtaking their northern world counterparts.

Part of the explanation lies in the fact that the United States has not had colonial or imperial ties to Africa, which meant that Baptists could not share the successes of British-based churches like Angli­cans, Meth­­odists, or Pres­by­terians or of French or Bel­gian Cath­olics. Baptists had some Afri­can presence, and pastor John Chilembwe be­came a hero of nationalist resistance in his native Mala­wi, but numbers were never large. Because Baptists never developed a serious foothold in Africa, they were in no position to benefit from the huge demographic expansion that has been a principal driver of church growth over the past half century. Nor could they compete with the enormously successful Pentecostal churches. Baptists were left without a potential niche in the market for souls.

In trying to explain the Baptist difference, however, we really should not be speaking in terms of a failure to launch globally. What sets Baptists apart from other churches is not a lack of growth around the world—in fact, their missions have been impressive—but their continued successes in the United States. Unlike mainline Prot­estant denominations, North America’s Baptists in recent decades have generally maintained their numbers. Matters might change in the future, but at present that success at home is the key explanation of why these churches have not been overwhelmed by emerging counterparts overseas. Not for the first time, Baptists are following a different path.

A version of this article appears in the May 10 print edition under the title “The Baptist exception.”