In my story, Earth follows an alternate history where this civilization has reached the same level of development as us, today. Assuming that this civilization can lift a second moon half the size of our current one into orbit around Earth and they had the funds to do it, why would they want to?
I have my premise down, but I still have no rationale for why they would do something so expensive for some unseen benefit.
Assume that the civilization is trying to lift this moon into orbit for the overall benefit of humanity, not just their own country. (for example, the dual moon system might allow for greater protection against asteroids, the dual moon might favorably impact tides for fishermen, etc.) Assume that the moon is lifted into orbit exactly across from our current moon. Also, assume that the gathering enough matter to create the moon has already been dealt with through some frantic handwaving (so there's no need to siphon off part of Earth's crust to make the moon).