The election of Hamas poses a significant test for what I usually call the hypothesis of inclusion. Do ideologically radical groups faced with the prosaic challenges of political responsibility choose pragmatism over rigidity? In general, the answer is that power tends to pull such groups to the center of the political spectrum. The Islamists, and other religiously informed groups such as the Christian fundamentalists Right in America, pose a particularly interesting variant of the question because they often avow an unconditional commitment to values allegedly informed by God or holy truths.
Here Abu Mazen is indicating that Hamas is now faced with precisely the signal choice that the hypothesis addresses.
Abbas Says Hamas Will Likely Soften Stance on Israel
Also see the remarks by a number of scholars at a recent and important conference in Boston.