I don't usually just swipe stuff from Antiwar.com, but this gobsmacking story really can't get enough exposure. When the UN Security Council passed its resolution on Gaza last Friday, the U.S. abstained—which was a major surprise to the UNSC's members, since the U.S. had been right at the center of the negotiations that led to the final document. I was surprised as well when I first heard about it; I would have expected either a vote or a veto (threatened, so that a vote would never have been called). So why the sudden change of heart?
Upon receiving word that the US was planning to vote in favor of the resolution - viewed by Israel as impractical and failing to address its security concerns - [Israeli prime minister Ehud] Olmert demanded to get Bush on the phone, and refused to back down after being told that the president was delivering a lecture in Philadelphia. Bush interrupted his lecture to answer Olmert's call, the premier said.
America could not vote in favor of such a resolution, Olmert told Bush. Soon afterwards, Rice abstained when votes were counted at the UN.
It's no rarity for the U.S. to take marching orders from Israel (search for "no-surprise rule" in the linked article), but it's rare to have it done so openly and in such a humiliating context, and rarer still to get such a direct account of it. This doesn't definitively answer the tail-or-dog question—mainly because there is no single answer—but it removes any doubt that there really is a meaningful question there.
[ See here for the original "We own your parliament" posting. ]
UPDATE: Some more details:
Mr Olmert said: "Mr Bush gave an order to the Secretary of State Rice and she did not vote in favour of it – a resolution she cooked up, phrased, organised and manoeuvred for. She was left pretty shamed and abstained on a resolution she arranged." [...]
I told [Bush], 'You can't vote in favour of this resolution'. He said, 'Listen, I don't know about it, I didn't see it, I'm not familiar with the phrasing'."
Mr Olmert then apparently brusquely told President Bush: "I'm familiar with it. You can't vote in favour."