During WW-II Ed Teller was reprimanded by Oppenheimer for working on thermonuclear weapon problems when he should have been focusing on fission weapons. Teller is/was genuinely brilliant though ethically challenged. The Teller-Ulam configuration which made thermonuclear weapons practical was a technical masterpiece. Study the history of thermonuclear weapons development and you'll find they did not get it right on the first pop. They got stuck on boosted fission for the longest while. There was a whole string a atmospheric bomb tests that were failures as thermonuclear weapons but made a big bangs anyway from their fission triggers. However once the Teller-Ulam configuration was proven effective then the world was changed forever. The success of the Mike Device proved to the Soviet nuclear weapons designers that thermonuclear weapons were indeed practical. It's conceivably they could have incorrectly concluded the problem was too hard. Stalin would have been forced to build his entire nuclear arsenal around fission weapons. The level of danger to the human race would have been considerably reduced.

Gary