Why did the u. s start making hydrogen bombs

The US started making hydrogen bombs when the USSR succeeded in creating an atomic bomb. The United States used to have the largest bomb, but when the USSR surpassed them, the US decided to create a better bomb (theorized to be hundreds of times larger than any nuclear bomb ever made).

The U.S. started majorly developing hydrogen bombs in the years following WWII, what is known as the Cold War. During this time the U.S. competitively built nuclear weapons in response to the Soviet Union/ Russia building nuclear weapons. Hope this helps.

C. congress was able to pay debts run up in the war