Since its inception in the early nineteenth century, the basic tenet of dispensationalism (a school of Protestant theology which holds that God deals with humankind in different ways in different periods of time called dispensations) has been that the church and Israel are two sharply distinct peoples of God. The distinction is theological in nature; specifically, anthropological (pertaining to humanity), soteriological (pertaining to salvation), and eschatological (pertaining to last things). The tenet of theological distinctiveness has always been the cornerstone for the dispensationalist's belief in the pretribulation rapture of the church: the belief that at the first stage of Christ's two-stage second advent he will endue all who comprise the true church with a resurrected body like his own, and transport; i.e., rapture, all to heaven before the seven year period of turmoil known as the Tribulation begins on earth. The rapture marks the end of one dispensation when God focused his attention primarily on the church, and the start of another when God will focus his attention primarily on Israel. Today, almost two centuries later, progressive dispensationalists have rejected the view of a sharp theological distinction. From their study of Scripture they observe a soft non-theological distinction. They describe the church and Israel as different redemptive dimensions of the same humanity that share in a holistic and unified eternal salvation. An already and not yet eschatological framework is the cornerstone of their system. This thesis will argue that progressive dispensationalism cannot integrate the pretribulation rapture doctrine into its reconstructed dispensational system on any basis of theological distinctiveness between the church and Israel. This will be accomplished by first setting forth the theological systems of the three major forms of dispensationalism that have existed during its history, namely, classical, revised, and progressive dispensationalism, and second, by showing that each of three kinds of theological distinctiveness, namely, anthropological, soteriological, and eschatological distinctiveness, are present in the classical and revised systems and therefore these systems can support the rapture's integration, but are not present in the progressive system and therefore this system cannot support the rapture's integration. The thesis closes with an explanation as to why progressive dispensationalism is more compatible with amillennialism than with premillennialism.