Calvinism is a theological orientation, not a denomination or organization. The Puritans were Calvinist. Presbyterians descend from Scottish Calvinists. Many early Baptists were Calvinist. But in the 19th century, Protestantism moved toward the non-Calvinist belief that humans must consent to their own salvation — an optimistic, quintessentially American belief. In the United States today, one large denomination, the Presbyterian Church in America, is unapologetically Calvinist.

But in the last 30 years or so, Calvinists have gained prominence in other branches of Protestantism, and at churches that used to worry little about theology. In 1994, when Mark Dever interviewed at Capitol Hill Baptist Church, a Southern Baptist church in Washington, the hiring committee didn’t even ask him about his theology.

“So I said, ‘Let me think about what you wouldn’t like about me, if you knew,’ ” Mr. Dever recalled. And he told them that he was a Calvinist. “And I had to explain to them what that meant. I didn’t want to move my wife and children here and lose the job.”

Mr. Dever, 53, said that when he took over in 1994, about 130 members attended on Sundays, and their average age was 70. Today, the church gets about 1,000 worshipers, with an average age of 30. And while Mr. Dever tends not to mention Calvin in his sermons, his educated audience, many of whom work in politics, knows, and likes, what it is hearing.

“I think it is apparent in his teaching,” said Sarah Rotman, 34, who works for the World Bank. “The real focus on Scripture, and that all the answers we seek in this life can be found in the word of God. In a lot of his preaching, he does really talk about our sinfulness and our need of the Savior.”