Claim. The True Parents are the single axis connecting the spirit world and the earth — and that need is infinite, not time-bound like a presidency or kingship.
Elaboration. SMM frames the role as cosmic-structural: “We must unite the world together with the True Parents. Through the heart of God, the axis of the spirit world and the axis of the earth have to be united with the True Parents. You cannot take True Parents out of the center of the spirit world or the earth” (3.2. True Parents are the axis, 149-279, 1986.12.7). The duration is unbounded: “Is there a limit to the need for the True Parents? There is none. Whether in this world or in the spirit world, this need is infinite… In four to eight years, the American president has to pack his bags, but that is not the case with the True Parents. The True Parents are needed not just in this earthly world but also in the spirit world” (3.3. True Parents is the center, 205-255, 1990.9.9). The two worlds cannot have a palace of love built from inside the spirit world alone; only earthly True Parents can build it for both.
See also. csg-heaven-is-empty-until-true-parents