In this paper, I examine the reason for the subsidence of Soviet dispute over philosophical legitimation of modern physics in the late 1930s. The battle of scientists against party ideologues or their sympathizers was politically adventurous in the period of the Great Terror. In fact, established scientists such as Nikolai Vavilov were severely accused by opponents and were led even to be imprisoned. However, in spite of the heated attack to some leading physicists in the dispute over modern physics in philosophical journals, the worst tragedy was avoided in general. I maintain that Sergei Vavilov, one of the most influential physicists of this period, acted as a crucial negotiator in this process. By learning the Marxist terminology or a politically correct attitude in the discourse, Vavilov succeeded in soothing the party ideologues and at the same time guarding modern physics or physicists. In some respect he made a compromise, but it was a very valuable one.