How did The Doctor take Harriet Jones down in the Christmas Invasion?

Question

At the end of the Christmas Invasion episode, after Harriet Jones orders to shoot down the alien spaceship, the Doctor, visibly mad, tells her he could take her down with a single word, or rather six.

The exchange went like this:

DOCTOR: Don't challenge me, Harriet Jones, because I'm a completely new man. I could bring down your Government with a single word.

HARRIET: You're the most remarkable man I've ever met, but I don't think you're quite capable of that.

DOCTOR: No, you're right. Not a single word, just six.

HARRIET: I don't think so.

DOCTOR: Six words.

HARRIET: Stop it!

DOCTOR: Six.

(The Doctor goes over to Alex and whispers in his ear.)

DOCTOR: Don't you think she looks tired?

(The Doctor, Rose, Mickey and Jackie leave.)

HARRIET: What did he say?

ALEX: Oh, well, nothing, really.

HARRIET: What did he say?

ALEX: Nothing. I don't know.

HARRIET: Doctor! Doctor, what did you? What was that? What did he say? What did you say, Doctor? Doctor! I'm sorry.

After that, we see glimpses of BBC news reporting a possible vote of no confidence over Jones, and an interview with her in which she insists she's fit and can do the job.

I never understood what actually happen. Did the Doctor hypnotize Alex, the assistant? How did they go from those six words spoken to him, to the Parliament moving for a vote of no confident against Harriet Jones? I'm not british, so I have very little idea of how Parliament governments work.

Answer 1

To better understand the significance of what the Doctor said to Alex it helps to understand what a vote of no confidence means.

As per the Wikipedia definition:

A motion of no-confidence or, alternatively vote of no confidence, is a statement or vote which states that a person(s) in a position of responsibility (government, managerial, etc.) is no longer deemed fit to hold that position, perhaps because they are inadequate in some respect, are failing to carry out obligations, or are making decisions that other members feel detrimental. As a parliamentary motion, it demonstrates to the head of state that the elected parliament no longer has confidence in (one or more members of) the appointed government.

To paraphrase for this specific situation. When the Doctor says to Alex, "Don't you think she (Harriet) looks tired." It's planting the seed in Alex to question if Harriet is fit to continue being Prime Minister, or if she is 'too tired'.

These 6 words spoken to Alex, Harriet's Sr. aide, inevitably leads to Harriet's downfall and being voted out of office under the presumption that she is no longer fit to lead.

Answer 2

This is an example of the old saw, 'Perception is reality.'

The Doctor knew that Harriet Jones would not keep her job if a significant portion of her constituents and the Parliament felt she did not belong there. And the simplest way to shift opinion is to plant a seed of doubt about her. He planted that seed by asking Alex the innocuous, but leading, question: "Don't you think she looks tired?"

The implication is that Alex, thinking about and later repeating that, would be the source of a memetic thought that would undermine Harriet Jones' position across a wide swath of the population. It is not that Alex held a position of authority; it's that the simple thought, easily repeated, could spread enough to undermine Jones.

Answer 3

Along with the excellent answers already here, I wanted to add that there's also an element here of a self-fulling prophecy.

Jones knows the Doctor is going to try to undermine her, she finds out the "innocuous thing" the Doctor said, and - to get out in front of the Doctor's smear campaign - will loudly proclaim that she "Is in fact, not only 'not tired' but full of energy and definitely fit to lead", thereby substantiating and helping spread the rumor that she's tired and unfit to lead the government.

So this added to the vote of no confidence . . .