Can anyone identify a book about multiple Lunar expeditions which encountered Venusian invaders?
It may have been a Badger Book, and was apparently written just after WW2, as it refers to Marshal Petain being sentenced to death (which he was) and shot (which he wasn't).
A scientist named Leinster has invented a new weapon, which for some reason is best employed from a Lunar base. Being an idealistic type, he sends details of it to all nations at once, rather than let any one have a monopoly.
This triggers a frantic "Race to the Moon", with expeditions from the US, Russia, China, GB, France, Germany and India. The first few chapters include potted histories of the countries concerned.
On arrival, they find that an expedition from Venus has already arrived. Venus is a dictatorship, and plans to impose the "Venusian System" on Earth. Iirc the Venusian astronauts are named Rustag, Klusak and Korio, or similar, and Korio is the "good Venusian" who averts war.
One memorable quote. The Chinese Captain reflects on how their Great Leader was always right, and that. "If the Great Leader said something today which contradicted something he had said yesterday, the important thing was that yesterday was dead. If one forgot that yesterday was dead, one was liable to join yesterday".