A former foreign policy adviser to Palestinian Authority Chairman Mahmoud Abbas said this week that the Hamas takeover of the Gaza Strip marks the "end of one party rule" in the PA, and that any future peace deal must involve the Islamist movement. Speaking at a briefing organized by the Arab American Institute and Americans for Peace Now, Ghaith al-Omari, a senior research fellow at the New America Foundation in Washington, said a new situation had emerged in which Hamas was in charge in Gaza and was "there to stay." "A new reality has come on the ground," said Omari. "[And] one thing that is very clear is that Hamas will not be dislodged from Gaza." A new Hamas-Fatah unity government would need to be established if there were to be any chance of peace, he said. "If Hamas feels that they have no stake in this peace process, they will and they can be major spoilers. All it takes is a few terror attacks in Israel to derail the peace process," Omari said. It was necessary to involve Hamas in the government because if it did not have the power it felt it deserved, it would resort to "military" means to acquire it, he said. "Any new arrangement that is going to be stable has to bring in Hamas in both the security sector and the political sector, but with the right conditions," he said. In the meantime, Omari said the international community must strengthen Abbas's new emergency government under Prime Minister Salaam Fayad to contain Hamas to Gaza. In addition, he said Hamas must be "squeezed a little" in order to send the message that "taking over by violence doesn't pay." Omari said that when negotiating over Gaza in the immediate future, when no PA unity government exists, the United States and Israel must speak to Abbas - not Hamas. "As for who you talk to right now, absolutely, completely, without any reservation, it has to be Abu Mazen [Abbas]," said Omari. "If you talk to Hamas right now it will be rewarding them in an unprecedented way for what happened in Gaza." Hamas's victory in Gaza has dispelled two common misconceptions, Omari said. The first was the belief that Hamas's role in Palestinian affairs could be minimized through military force. The second misconception Hamas's victory dispelled, according to Omari, was that Hamas could rule Gaza by itself. "We are already seeing some signs of their confusion," said Omari, who cited Hamas's promise to release BBC correspondent Alan Johnston, and their subsequent inability, or unwillingness, to do so as proof of such. "We are seeing that Hamas's 'good intentions' are going to hit reality and soon they will realize that they will have to change their approach," he said.