That Truman and Ike were forced to negotiate with them about how the USA was going to operate under the Nazi International's control and directions. etc. etc. etc.
Rather preposterous stuff ... unless there's some truth to it.
Admiral Byrd went on an expedition (operation High Jump) there after WWII. While it was stated to be for exploration, the ships included seemed more like an armada.
The trip was cut short, and ships were damaged. Parts of the record are still classified per what I have read. Another theory is that the Nazi's did have some advanced high powered weapons that they used to attack the fleet.
A snippet from an interview with Admiral Byrd:
“Admiral Richard E. Byrd warned today that the United States should adopt measures of protection against the possibility of an invasion of the country by hostile planes coming from the polar regions.
The admiral explained that he was not trying to scare anyone, but the cruel reality is that in case of a new war, the United States could be attacked by planes flying over one or both poles.
This statement was made as part of a recapitulation of his own polar experience, in an exclusive interview with International News Service.
Wiki Leaks released photos of Antarctica too. Just one more mystery that remains hidden for now.