After World War II ended, Bethe worked with [[Edward Teller]] to help develop the [[hydrogen bomb]]. But he also helped negotiate the 1963 partial test ban treaty with the Soviet Union, and advised several Democratic presidents. Late in life Bethe advocated against the development of defensive nuclear systems. | After World War II ended, Bethe worked with [[Edward Teller]] to help develop the [[hydrogen bomb]]. But he also helped negotiate the 1963 partial test ban treaty with the Soviet Union, and advised several Democratic presidents. Late in life Bethe advocated against the development of defensive nuclear systems. |