Capitalization and Underscoring in book titles

Recently a I-know-it-all-and-u-r-dumb commentor told me I was totally wrong about claiming the refernce to the Law of Nations meant to Vattel work. Some might agree but some would be WRONG!. The commenter remarked that the tital shouldbe capitalized and underscored. well, it is capitalized indicating the words relate to something specific. It is NOT underscored. Here's the rub. This commenter is ignorant of uncerscoring. So when did underscoring become part of writing? The answer is when the first typewriter was invented. The forst typewriters could not italicize things because the typeface on the keys was fixed. So Writers/publishers came up with underscoring in order to demonstrate the importance of the words as related to another work. Underscoring is modern and not something the Framers would have done simply because there were no typewriters when the Constitution was written. Sorry for the I-know-it-all commenter but YOU ARE WRONG.