Mysterious Mr. Sabin by E. Phillips Oppenheim

Of all unhappy men he is assuredly the most unhappy who, ambitious, patient, and doggedly persevering, has chosen the moment to make his supreme venture and having made it has reaped failure instead of success. The gambler while he lives may play again; the miser, robbed, embark once more upon his furtive task of hoarding money; even the rejected lover need not despair of some day, somewhere finding happiness, since no one heart has a monopoly of love. But to him who aspires to shape the destiny of nations, to control the varying interests of great powers and play upon the emotions of whole peoples, there is never vouchsafed more than one opportunity.

And failure then does more than bring upon the schemer the execration of the world he would have controlled: it clears eyes into which he had thrown dust, awakens passions he had lulled to sleep, provokes hostility where he had made false peace, and renders for ever impossible the recombination of conditions under which alone he could, if at all, succeed. For such an one life has lost all its savour. Existence may perhaps be permitted to him, but no more. He stakes his all upon one single venture, and, win or lose, he has no second throw. Failure is absolute, and spells despair.