It will be decided the same way “Mr. President” was chosen: the person holding the office will give her preferred form.
Madame President has tradition, but Ms. is more modern. I would assume a Republican president would choose the former, while a Democratic president would use the latter.
“Madam Pelosi” returns 300,000 Google hits, while “Madame Pelosi” only gets 139,000. So it appears there’s already some confusion over this convention.
“Madam” is the usual form of address for higher level government officials, including Cabinet Secretaries, Supreme Court Justices, Speaker of the House, Ambassadors, etc. So “Madam President” would be the most appropriate.
http://www.cftech.com/BrainBank/OTHERREFERENCE/FORMSOFADDRESS/SpkWritFrmsAddr.html
FWIW, the UK gets around this problem thusly: the Prime Minister is addressed just as “Prime Minister” (or The Right Honorable Prime Minister, formally) whether male or female.
“Mr. President” has always sounded really odd to me, as do its cousins “Mr. Chairman”, “Mr. Secretary”, etc.
Now there is a good reason to try and get the first woman president!.
Is there a good story behind “Mr. President”?
Isn’t “Mrs.” sometimes used in the etiquette books to mean “the wife of” (as in “Mrs. John Smith”)?
I’d hesitate to call a female president “Mrs. President” since this could be interpreted to mean “the wife of the president” according to this admittedly old-fashioned usage.
As I recall, Washington didn’t much care for other forms of address being suggested, including My Lord, Your Majesty, etc.
The term she’s addressed by is ‘Madame Speaker’.
I don’t remember the exact story, but there was a (possibly apocryphal) story we were told in history. It went along the lines of they were trying to think of what to call the president and different things popped up, i.e. Your Majesty (because he was called the chief magistrate in those days), lord etc. Since they wanted to stay away from aristocracy and the old monarchy and whatnot they all were stuck. One day at a party someone (I think it was Adams or something, but it may have just been a random guy) just said “Hello, Mister President.” And it stuck. (Some versions give it as “Happy Birthday, Mister President!” Which may also work but I think they’re conflating it with the song Marilyn Monroe did for JFK.)
The strikes me as possible, but it also sounds like one of those stories made up after the fact to explain things. Maybe someone more versed in folklore (or history) can remember a better retelling.
Right, but “Madame Speaker” would bring up a buncha unrelated hits, presumably.
It’s unlikely that Adams came up with “Mr. President” for a few reasons. First, he was the one who got lambasted for wasting the Senate’s time with resolutions that the President should be addressed as “His High Mightiness” and other nonsense. (This earned Adams the sobriquet “His Rotundity.”)
Second, “Mr. President” was used as a form of address for the presiding officer of several bodies before Washington was President, such as the President of the Confederation Congress. Adams himself may have been addressed as such when presiding over the Senate, though I don’t know if that tradition had caught on yet.
As for a female President, the form of address would be Madam President, following the same tradition as other “Mr.” titles which have been feminized, such as Madam Speaker, Madam Secretary, and Madam Justice.
Hence why I said “Adams, or something” I knew there was someone who got in trouble like that but I couldn’t quite recall who. Anyway, thanks for clearing that up.
I’m partial to putting emphasis on on the second syllable. Ma’ Damn President.
Or if coughing fit gets elected, and important death ensues, Mad!-am President.
Before the term “First Lady” came into widespread use the wife of the President was occasionaly addresed as “Mrs President” or “Mrs Presidentess”. Martha Washinton was often refered to as “the Lady Washington”. The proper, formal way to address the First Lady remains simply "Mrs Smith. A First Lady who used her maiden name would of course be “Ms Doe”. For certain matters (diplomatic correspondence, overseas visits, UN events, etc) the President is actually entitled to use “Execellency” as is standard for non-royal heads of state.
The etiquette answer:
Given the two choices presented, ‘Ms. President’ would be correct. Not politically correct, actually correct. ‘Ms.’ is a proper honorific for any woman when it isn’t necessary or desired to indicate marital status. ‘Ms.’ is, in this context, the exact equivalent of ‘Mr.’
‘Mrs.’ means, properly, ‘wife of.’ So, ‘Mrs. President’ would mean, ‘wife of the President.’ Not correct, in other words.
All that said, when the situation arises, the usage will probably be ‘Madame President,’ since that is the protocol used in similar situations (Madama Speaker, Madame Governor, etc.)
I thought governors were addressed simply as “Governor”. I’ve never heard the term “Mr Governor” used. Some states (PA, New England, and I think a few Southern states) retain the formal style of “Execellency”. And one would only ever say (or write) Mr/Madam President if speaking (writing) directly to the President. In the 3rd person it’s “the President (of the United States)” or “President Smith”.
Look, I’ve already had to remind one person about GQ standards. Political jabs are not permitted, as you should know.
Colibri
General Questions Moderator
/http://www.washingtonpost.com/wp-dyn/content/article/2006/06/20/AR2006062001207.html
Miss Manners has decreed it. I would not dare to argue the point. 
The first four hits on google.ca for “Madame Speaker”, with quotes, are about Ms Pelosi - first 5 without - for the record.
The 6th hit without quotes is protocol for addressing members of the Canadian government, which presents ‘Madame Speaker’ as the correct form of address for a female Speaker.