The
Manhattan Project had already ended by the time
Operation Paperclip was implemented. In fact, very few of the German scientists and engineers recruited as part of it were
nuclear scientists; by far the majority were involved in
aeronautics and
rocket science.
Operation Paperclip was aimed at recovering all or substantially all of the research and development conducted by Nazi Germany during WWII, and in this was massively successful. The amount of paper recovered filled several large warehouses at the National Archives. A key component of Operation Paperclip, controversial at the time, was to bring the key engineering and scientific personnel as well.
The truth is that a large percentage of the scientists and engineers were not in fact ardent Nazis themselves, but had joined the party in order to continue their careers. Among this number was Werner von Braun, who joined the party only when it became necessary to continue his rocket work.
The White Sands group was not in fact involved in nuclear work; they were working with captured V2 missiles, launching them for research and scientific purposes. These were the first sounding rockets, and formed the basis for the US missile and space programs.