The pledge to USE my discovery is the one all-important point--it must be a solemn, binding pledge--never to be broken." Gwent puffed slowly at his cigar.
"It's a bit puzzling!"-- he said--"When and where should it be used ?" Seaton stretched out a hand argumentatively.
"Now listen!" he said--"Suppose two nations quarrel--or rather, their governments and their press force them to quarrel--the United States (possessing my discovery) steps between and says--'Very well! The first move towards war--the first gun fired--means annihilation for one of you or both! We hold the power to do this!'" Gwent drew his cigar from his lips.
"Annihilation!" he murmured--"Annihilation?
For one or both!" "Just so--absolute annihilation!" and Seaton smiled with a pleasant air of triumph--"A holocaust of microbes! The United States must let the whole world know of their ability to do this (without giving away my discovery).

They must say to the nations 'We will have no more wars.

If innocent people are to be killed, they can be killed quite as easily in one way as another, and our way will cost nothing--neither ships nor ammunition nor guns.' And, of course, the disputants will be given time to decide their own fate for themselves." Sam Gwent, holding his cigar between his fingers and looking meditatively at its glowing end, smiled shrewdly.
"All very well!"-- he said--"But you forget money interests.

Money interests always start a war--it isn't nations that do it, it's 'companies.' Your stuff won't annihilate companies all over the globe.
Governments are not likely to damage their own financial moves.

Suppose the United States government agreed to your proposition and took the sole possession and proprietorship of your discovery, and gave you their written, signed and sealed pledge to use it, it doesn't at all follow that they would not break that pledge at the first opportunity.
In these days governments break promises as easily as eggshells.