The answer to this question is socialization :)
When you think of a channel think of trade. Or boats going up and down a stream, a channel is a body of water.
Viewed by many as Lincoln’s greatest speech, this address declared that slavery was the war’s essential cause and that the war was an expiation of the national sin of slavery. Speaking transcendently to history, President Lincoln explained the Civil War—its cause, its character, and its immediate consequences. Though he wanted to be clear that slavery caused “this mighty scourge of war,” he ended on a hopeful note of binding up the nation’s wounds. His message of “charity for all” diverted some Republican desires for harsh retribution against the South.