From a speech given by U.S. President Woodrow Wilson before the start of the first World War:
We want one class to have a liberal education. We want another class, a very much larger class of necessity, to forgo the privilege of a liberal education and fit themselves to perform specific difficult manual tasks.
The shocking thing isn’t that this was the objective of the public education system, but that it was openly admitted. For more details and supporting evidence, read The Underground History of American Education by John Taylor Gatto. The full text of the book can be read online.