Bush knows that talks cannot move ahead without different person/people leading the PA. Without that, talks would be a wasted effort. The American plan calls for structural changse that would lead to Arafat's removal from power. The Bush advisors have proposed the establishment of a temporary government within the PA until a constitution is drawn up and elections are held. No talks between Israel and the PA until those internal reforms are complete. Once they have been carried out, the President demands that the two sides talk toward final settlement.
And that's okay. Bush and Sharon have already agreed to jettison Arafat. It's just a matter of how it is to be done. Sharon wants to put him on a plane to Timbuktu. Bush wants to castrate him but leave him in the area so he doesn't become a martyr. Hell, he may even become a champion of peace--it's pretty clear his mind is slipping.
I don't think Sharon plans a long incursion in response to the latest bombing. It may just be an airstrike or five in Gaza. That'd be my guess.
The real interesting part is going to be watching how Bush replaces Arafat as head of the Palestinians. That's obviously something he's been formulating for a couple of months now.