Apparently Stalin said during the Rhineland crisis that if war broke out between any of the western nations that the Soviets would sit out until the winner was clear then dogpile in on the winning side just to say their piece at the peace conference.
History is full of such politicking!
(Think of Sweden in the War of the Sixth Coalition, for example.)
Of course, by 1938, Stalin was worried enough to start exploring a more energetic involvement...