 Returning from Sweden by way of the United States, he visited the American headquarters of the Covenant church in Chicago.While there, he enrolled as an undergraduate at Wheaton College, an evangelical institution, where he applied credits from China and worked straight through in order to graduate in one year, at the age of thirty-eight.Upon his return, Cheng joined what historian Daniel Bays calls the "Sino-Foreign Protestant Establishment," which included such figures as Zhao Zichen, David Z. T. Yui, and Frank Rawlinson, whose theology was more liberal than Cheng's fundamentalism.