Spelling “President” with a small “p”?

I do not remember the name of the professor teaching English 101 who told the class  when referring to the President of the United States of America, you must use a capital “P”. He said that is due to respect for the office and also separates him from the president of a club, company or other entities. I have never forgotten that lesson learned so many years ago and often wonder why other 101 English Teachers do not teach their students the same rule.
As always,
BB

 Obama, congressional leaders fail to reach deal on sequester
Excerpt:
The president and Congress created the sequester in 2011 to force themselves to find smarter ways to reduce the deficit.
Read more at:
http://www.washingtonpost.com/politics/obama-meets-congressional-leaders-on-sequester/2013/03/01/fa25a440-827b-11e2-b99e-6baf4ebe42df_story_1.html