"This radical transformation of world power relationships reflects primarily in the case of both the USA and the USSR the growth of the productive forces"

Earl Browder's quote concentrates on the dramatic shifts in international power characteristics, primarily driven by the advances in productive forces in the United States and the USSR. The phrase "extreme change of world power relationships" recommends a considerable change in how impact and authority are distributed among countries. This change can be credited to the growth in productive capabilities, that include technological developments, commercial capacity, and financial development.

For both the USA and the USSR, the mid-20th century was a period of quick expansion and modernization. In the United States, the post-World War II era saw enormous industrial growth and a flourishing economy, supported by technological developments and a boost in consumer culture. This solidified the USA's position as a global superpower with unrivaled economic and military strength.

Similarly, the USSR experienced substantial commercial growth, mainly driven by its central preparation system that focused on fast industrialization and scientific development. The Soviet Union's capability to establish nuclear innovation and complete in the arms race with the USA even more improved its status as a worldwide power, challenging the previously unipolar world order controlled by Western powers.

Browder suggests that these productive forces are not merely economic in nature however also encompass political and social modifications within these countries. The USA's growth fueled a capitalist model that supported political freedoms and private liberties, while the USSR's socialist system aimed to rearrange resources more equitably.

In conclusion, Browder's quote encapsulates the essence of the Cold War age-- a time when the USA and USSR became superpowers not exclusively due to military may but because of substantial developments in their efficient capabilities. This change not just altered worldwide politics but also set the phase for ideological competitors between capitalism and socialism, affecting global alliances and conflicts for decades.