Is Sharon abandoning Gaza to make Washington happy?

I continuously look for reasons for the disengagement that makes sense. In a Jerusalem Post op-ed, one reason is given (although this is not the point of the article:

One explanation for Prime Minister Ariel Sharon's about-face on the settlements, his willingness to uproot what he himself planted, is that in his mind as a statesman – rather than in his view as a general – a close strategic relationship with the US will do more to protect Jerusalem, Tel Aviv and Netanya 50 years down the line than a hilltop settlement.

When Sharon is asked what he is getting for disengagement from Gaza, he – or his aides – reply that they are not getting anything from the Palestinian Authority, but are getting something very substantial from Washington: commitments that the US will back Israel's position on the Palestinian refugee issue and on retaining the large settlement blocs. This is far more important than a billion-dollar arms deal with Beijing.

Sharon has built up an unprecedented relationship with US President George W. Bush, but at the same time he has also stacked Israel's eggs in one basket to an unprecedented degree.

If this is the reason for the pullout, it makes no sense. While Sharon and Bush do have a close relationship, what good does that do Israel when either of them are out of office? To think that this will help things 50 years down the road, or even ten years from now, is foolish as well as foolhardy.