Editor’s Note: The following is Liz Smith’s interview with Helen Thomas on the upcoming, exclusive HBO documentary, ‘Thank You, Mr. President: Helen Thomas at the White House,’ which debuts Monday, August 18 (9:00-9:45 PM ET/PT). wOw’s Sheila Nevins was HBO’s executive producer behind the film. Click the link below to watch a sneak preview.

Helen Thomas has been called the "watchdog of democracy." Most people in media think of her as their implacable barometer of ethics and conscience. Now 88 years old, she stands at the top of White House press coverage, having worked for United Press International and, now, for the Hearst News Service.

Her awards are too numerous to list. Her integrity is beyond question. She is the Queen of Fairness. It is Helen who ends White House briefings by saying, “Thank you, Mr. President.”

Helen Thomas — in a class entirely by herself!

LIZ: Dear Miss Thomas, no kidding, which one of the presidents from John F. Kennedy to George Bush II has been your secret favorite? You never appeared to play favorites but you must have liked some better than others.

HELEN: John F. Kennedy. He was the most inspired; he had vision; he had been in war, and knew the difference between war and peace. He showed great courage in the Cuban Missile Crisis. He also encouraged young people to go into public service.

LIZ: Which of your many heroic actions in holding presidential feet to the fire have made you the most proud?

Click here for a sneak preview of "Thank You, Mr. President: Helen Thomas at the White House."

Click here for photos from the life and career of Helen Thomas.

HELEN: I don’t think proud is the word. The aim is not to embarrass or humiliate a president. It’s simply to find out their motivation and what has landed us in certain debacles. Presidents are vulnerable for anything they do.

LIZ: Did any of the presidents’ wives irritate or disillusion or attack you?

HELEN: Attack is a strong word, but I am not loved – I can assure you!

LIZ: Did any of them ever take you to task for treating their husbands with studied fairness?

HELEN: In the end, I think most of my relationships with First Ladies have worked out with great understanding. But there’s no reason why we should be liked when we are critical and watching every move presidents make, but that’s the price of living in the White House.

LIZ: Has anyone ever tried to bribe you? I know people have always tried to influence you, in vain.

HELEN: Never – nobody has tried to bribe me.

LIZ: Did you get invited to White House dinners? How did that go?

HELEN: Like many people, I have attended White House dinners. Every president’s family (until recently) has invited me as part of the press corps to State dinners, but other reporters have also been invited. I have been honored to be invited.

LIZ: Did anyone ever suggest that you should go into politics or into public relations?

HELEN: As a gag – if elected, I will serve. Meantime, you can find a female president in my new children’s book, The Great White House Breakout.

LIZ: CBS’s late Fred Friendly used to keep a copy of the Constitution in his back pocket. Do you have anything like that, perhaps a good luck charm, an amulet or a piece of Americana to inspire you?

HELEN: I have a copy of the Constitution which I carry or keep in a drawer at my office. I’d like to present it to a president so he would know the limitations of his power.

LIZ: What was the most exciting presidency of your presidential coverage life?

HELEN: The Kennedy and Johnson administrations. They were innovative and visionary. With LBJ, it was a three-ring circus, and you never knew what he had up his sleeve.

LIZ: Didn’t you wait quite a long time to marry? Why did you resist for so long?

HELEN: I didn’t have that many offers!

LIZ: Have you ever sat on a story or a scoop for the good of someone or the good of the country?

HELEN: I don’t think so.