[I quoted the first sentence of this before, but in light of current Republican attacks against the teaching of history it seemed worthwhile to revisit it and include more. Emphasis added]
"Upon the subject of education, not presuming to dictate any plan or system respecting it, I can only say that I view it as the most important subject which we as a people can be engaged in. That every man may receive at least a moderate education, and thereby be enabled to read the histories of his own and other countries, by which he may duly appreciate the value of our free institutions, appears to be an object of vital importance, even on this account alone, to say nothing of the advantages and satisfaction to be derived from all being able to read the Scriptures, and other works both of a religious and moral nature, for themselves." -- Abraham Lincoln (b. 1809-02-12, d. 1865-04-15; 16th President of the United States 1861-03-04to 1865-04-15), 1832-03-09 (dated "around 1 March" in the linked source, dated 9 March in Wikiquote).
[While Lincoln justified it to "duly appreciate the value of our free institutions," it seems to me that appreciating what we got wrong, how we got here, and how we might do better, are all at least as important to anyone who truly loves their country, not so we can lay blame or feel guilty or hate anyone, but so we can understand why things are as they are and how they can be made more just in the future.]