Well - Patriotism has its laws. And it also is a perfectly definite one, there are not vaguenesses about it. It commands that the brother over the border shall be sharply watched and brought to book every time he does us a hurt or offends us with an insult.

Mark Twain at Your Fingertips: A Book of Quotations (ed. Courier Corporation, 2009) - ISBN: 9780486473192