great white hope

Someone or something expected to succeed or on whom/which certain hopes are based. Many have come to regard the presidential candidate as a great white hope for a new era of social reform and economic prosperity. The new video game console is widely seen as the foundering company's last great white hope.

Something or someone that is expected to succeed. For example, Mark is the great white hope of the international division. This expression dates from the early 1900s, when heavyweight boxing champion Jack Johnson, who was black, seemed invincible and the term was used for any white opponent who might defeat him. It gained currency as the title of a Broadway play and later (1970) a film. By then it had been transferred to anyone of whom much was expected.