Which one of the following U.S. Presidents — who fought in the defense of Baltimore during the War of 1812 — never attained a rank higher than private?

Which one of the following U.S. Presidents — who fought in the defense of Baltimore during the War of 1812 — never attained a rank higher than private?

Abraham Lincoln
Andrew Jackson
James Buchanan
William Harrison
Zachary Taylor

Correct Answer: James Buchanan