The time to stop a revolution is at the beginning, not the end.

Adlai Stevenson II (1900–1965) American politician, diplomat, statesman
Speech (1952-09-09), “World Policy,” Veterans Memorial Auditorium, San Francisco, California
    (Source)

Criticizing tardy attacks from the Right about "Who lost China?" to its Communist Revolution, after the same complainers had shown no interest in supporting the Republic of China forces early on.