To a large extent, US policy has allowed Hamas to create its terror statelet in Gaza.
The 2006 elections where Hamas beat Fatah took place mostly because Bush was on his democracy kick - and he made the mistake of confusing democracy with elections. He read and admired Natan Sharansky's book, and misunderstood it. Real democracy requires freedom as a prerequisite, something that certainly didn't apply in the PalArab territories.
As a result, Hamas emerged stronger than ever and is now on its way to building an Islamist thugocracy - the exact opposite of the Bush administration's intent.
And it appears that the lessons have not yet been learned.
(Blogging from Blackberry so no links to relevant articles, sorry.)
