C.N+Had+he+the+power+he'd+effaceThe+history+of+the+human+race

The line "Had he the power he'd efface,The history of the human race" is very key to the poem because it sets the tone for the poem and contributes a lot to the message trying to be made. What the author is trying to say in this line is that If the world were run by men who said "It can't be done" than everything that the human race has accomplished would never have been done because these men would never have the courage to do them. For example in the poem it lists various things that people use everyday like cars,street lights,and cell phones that wouldn't have been invented if the world was run by men who say "It can't be done".