The deal brings with it the risk of alienating the Western support that the Palestinian Authority has enjoyed. Azzam al-Ahmad, the Fatah negotiator, said that Salam Fayyad, the prime minister in the West Bank who is despised by Hamas, would not be part of the interim government. It is partly because of Mr. Fayyad, and the trust he inspires in Washington, that hundreds of millions of dollars are provided annually to the Palestinian Authority by Congress. Without that aid, the Palestinian Authority would face great difficulties.
The announcement was sure to fuel a debate on whether Mr. Netanyahu had done enough in his two years in power to forge a deal with the Palestinian Authority led by President Mahmoud Abbas and Mr. Fayyad, widely considered the most moderate leaders the Palestinians have ever had.