Media playback is unsupported on your device Media caption How the White House's story on Comey collapsed

What if the Comey firing is nothing to do with the Russia probe or the Clinton email server but is actually just a result of the president's thin-skinned character?

And would that be more or less alarming than Comey being fired in order to impede the Russia investigation, which is the case Democrats are making this week?

New reporting from the Washington Post, and other US media outlets, which are the recipients of a huge amount of leaks this week, suggest Mr Trump was upset by the Comey testimony at the Senate last week.

What particularly angered him, the reports say, was Comey saying it made him "mildly nauseous" to think the FBI may have swayed the election.

This hit right at President Trump's psychological weak spot - the legitimacy of his victory in the election.

Mr Trump frequently talks up the size of his win in November and often disparages people, or photos, or agencies that suggest he didn't win big. He still does so, six months after the election.

But is being thin-skinned now getting in the way of his ability to do his job effectively? The sacking of James Comey might be evidence of that.

Mr Trump hated what he heard in Mr Comey's testimony. It made him angry, he felt disparaged and he hit back. This, we understand, was Mr Trump's MO as a business man.

But the scale now is far larger and he hit back in a way that undermines his credibility (because the story is not straight) and diminishes trust in the institutions of government.

This may be about the Russia probe getting more intense, but there is still no evidence that Mr Trump colluded with Moscow to affect the outcome of the vote. None.

It doesn't look good that the White House fires the man who's in charge of the investigation but it may be just that, unfortunate optics.

But it may simply be about Mr Trump's personality. He doesn't forgive grudges and feels somehow unfairly treated. Then he acts fast, sometimes impulsively, especially when he's angry.

At 70 years old, his character is unlikely to change.

If the firing of Mr Comey is an example, it's not a good sign for long-term stability in this White House.