Answer:
by expanding the atomic weapons program that was already in existence
Step-by-step explanation:
President Truman had to inform US citizens of the schocking news: sooner thay they expected the White House saw Soviet state first succesful atomic explosion. The US cabinet assesed and decided to turn into an intensive evaluating of America's Cold War policy by the National Security Council. The report, that was approved in the early 1950 innitiated the arms race, furtherin increaing tensions between the superpowers. As a mass increase in military spendings and accelerated nuclear programs developed, the world quickly came into global tension next decade.
The Hydrogen bomb was the next step following this fierce competition for having supremacy.