Palestinian Prime Minister Mahmoud Abbas is threatening to resign unless given more latitude in his negotiations with Israel, according to the AP:

Palestinian Prime Minister Mahmoud Abbas threatened to quit as premier and resigned from a key body of Yasser Arafat's Fatah movement Tuesday, reflecting turmoil within the Palestinian leadership over negotiations with Israel....

Abbas has been facing strong pressure within his Fatah movement to adopt a tough line on the prisoner releases. In a letter to Arafat, he said he would step down as premier unless he gets clear instructions from Fatah over how to handle contacts with Israel....

Palestinian leaders proposed Monday that Abbas and security chief Mohammed Dahlan meet with Israeli Knesset members to help press Palestinian demands for a prisoner release. The meeting has yet to be scheduled.

Israel holds an estimated 7,000 Palestinian prisoners -- an issue that threatens to become a major crisis between the sides -- and this week Sharon's Cabinet decided to free perhaps 5 percent of them. Israel thought the planned prisoner release would strengthen Abbas' position. But top Palestinian officials say its limited scope could weaken Abbas by making him look ineffectual.

This will be an interesting test for the Palestinian leadership. Abbas' primary lever of power is that the Americans and Israelis will actually negotiate with him. The question is whether losing that link is costly enough to force the rest of Fatah to back down.