By Jonathan Beale
BBC News, Washington
Why would America's most senior military commander in the most volatile part of the world suddenly resign - well before his tour was over?
William Fallon had a track record of differing with the White House
President George W Bush is a man who values loyalty above all else. Admiral William "Fox" Fallon is a military man, apt to speak his mind.
The qualities admired in politics and the military are not always the same. And the bottom line is that some of the admiral's forthright views have sounded at odds with his Commander-in-Chief.
The last straw was a profile of Adm Fallon in Esquire magazine. Perhaps the admiral thought such a "lifestyle" publication - sandwiched between pictures of half-clad women - would not make front page news and he could let his guard down.
But the most senior US military commander in the Middle East clearly stepped over the line.
'In hot water again'
In the article, titled The Man Between War and Peace, Adm Fallon hardly comes across as a cheerleader of the Bush administration's policies in the region.
A navy admiral knows when it's time to "walk the plank" - perhaps some politicians could learn a lesson
He appears to take a swipe at his boss's recent rhetoric.
The article helpfully reminds us of Adm Fallon's comments to Al-Jazeera (not the White House's favourite television station) last autumn, when he said: "This constant drumbeat of conflict... is not helpful and not useful."
He added: "I expect that there will be no war, and that is what we ought to be working for."
The author of the article, Thomas PM Barnett, clearly gained the confidence of Adm Fallon.
He writes how, on a trip to Cairo with the admiral, the latter told him "I'm in hot water again", when an Egyptian newspaper carried the headline "US rules out strike against Iran".
The article states that when the reporter asked: "With the White House?", the admiral nodded his head.
Eye off the ball
In offering his resignation, Adm Fallon and US Defence Secretary Robert Gates claimed that their "differences" were more about "misperception" than reality or substance.
Adm Fallon had appeared to take a swipe at George Bush's rhetoric
But were they? After all the admiral has a track record.
Last September, the Washington Post reported sources saying that Adm Fallon believed the surge in Iraq "was not working".
This February, the New York Times reported that Adm Fallon had spoken in favour of a "resumption" of US troop withdrawals in Iraq to ease the overall stress on the US military.
Talking to ABC on a trip to Afghanistan, he signalled that the US might have taken its eye off the ball on that country's growing insurgency because of Iraq.
So, both Adm Fallon and Mr Gates were probably trying just to paper over the cracks when they suggested this was mostly about misconstrued perceptions in the press.
However, Mr Gates was probably being more frank when he dismissed as "ridiculous" the suggestion in Esquire that Adm Fallon's early departure would signal the build-up to war in Iran.
Pushed or jumped?
The article was prescient in predicting Adm Fallon's exit, but perhaps not in the conclusion it drew.
A navy admiral knows when it's time to 'walk the plank'. Perhaps some politicians could learn a lesson
Yes, the Bush administration is genuinely concerned about Iran's nuclear programme and wants to keep the military option on the table.
But there is little to suggest that an attack is now being actively planned.
For one thing, you cannot have peace in the Middle East while bombing Iran. You cannot have stability in Iraq while attacking its volatile neighbour.
Adm Fallon is not the only military commander who has serious reservations about mounting such an attack.
We may never know whether Adm Fallon was pushed or whether he jumped. But, by announcing his departure, he did show another difference of character between military officers and politicians.
A navy man knows when it's time to "walk the plank". Perhaps some politicians could learn a lesson.