As for John McCain, I don't think he is an extrovert. I agree with SP, but ISP.
This blog makes a good case for ISFP, but I think ISTP is a solid possibility as well. Introverted feeling seems to be a conscious function for him, and behind the scenes seems to be his interaction style, not chart the course. He's right in the middle of things behind the scenes, screwing things up for the Republican Party with his maverick ways, but looking awkward and unplanned when he tried to make a big public splash on the economy-front last fall. That's not his way, as befits an introvert. But he's not the type to set back and work things out either, he's always in the thick of things. I like the ISFP possibility for him actually.
I also don't think Obama is an ENFJ. I think people project onto Obama a lot of traits he doesn't have, just like a consummate politician. I think he writes good speeches that use a lot of concrete language and examples and sound true to life, but they aren't the transcendant Ni speeches of an ENFJ (and he's not a good public speaker, he stumbles around a lot without his teleprompter, and sometimes with it).
I think Obama is a dominant perceiving type, not judging. He's open and presents his perceptiveness to the world, and that allows people to project their own hopes and dreams onto him. That blog makes a case for ESFP, Keirsey thinks INTJ (dominant Ni) or ENTP (dominant Ne). ENFJs are dominant feeling and I don't think that's Obama.
Please read
the text of his keynote address to the Democratic Convention in 2004 (back before he was famous, lol). It is full of details, a down-home concrete story-telling style. It displays a real way with words, the way they sound and work together. Very much like Franklin Roosevelt, who was an SP. I think he displays a real artfulness with regard to language and rhetoric, but what I don't see is a lot of profound ideas. His speech is grounded in common reality and shared experiences, which is the domain of extraverted sensing. It seems that whenever Obama uses phrases that go beyond this, they are the words of someone else (something his mamma said, or something Lincoln said).
On the other hand, Keirsey says his books are the only things that came from his own mind, unlike the speeches. And that is why Keirsey says NT. I don't know, but I just don't think he is an ENFJ or any kind of NF actually.
Nelson Mandela is an ENFJ. His
1994 inauguration speech is all about time (the domain of Ni), the future, building a bridge and bringing South Africa forward with the force of his vision. His
"the struggle is my life" statement from the 60s is an even stronger example of an ENFJ speech. He invents epic phrases rather than recalling the wise words of others.