Israel's acting Prime Minister Ehud Olmert has been appointed to form a new government. The challenge will be forming a stable coalition that can implement his ambitious plan to draw Israel's final borders over the next four years.

Ehud Olmert, left, and Moshe Katsav, right, deliver announcement to media at President's residence in Jerusalem, April 6, 2006

Just over a week after national elections, Mr. Olmert got the green light from Israeli President Moshe Katzav.

"I appoint Ehud Olmert to form the next government of Israel," Mr. Katzav said. "A government," he said, "that will bring economic prosperity and security."

The move was expected because Mr. Olmert's centrist Kadima party won the most seats in the Knesset, Israel's parliament.

At a joint news conference, Mr. Olmert said he would work to establish a stable government.

He said the government would work to implement his plan for Israeli withdrawals from large parts of the West Bank by 2010. The pullouts would be unilateral because with the election of the Islamic militant group Hamas in January, Israel says it does not have a Palestinian peace partner.

Mr. Olmert said he hopes to establish as broad a coalition as possible. That means he will try to recruit hawkish right-wing parties that are lukewarm to the pullout. The reason is that Kadima won only 28 out of 120 parliamentary seats. He needs the right-wing parties to establish a more stable government, and to diminish what is bound to be fierce opposition to the withdrawal.

Mr. Olmert will have to move slowly to keep such a government intact. Analysts say he will probably wait two years before he begins implementing the pullout, which calls for the removal of about 70,000 Jewish settlers from their homes in the West Bank.

If the past is any yardstick, the right-wing parties might quit the coalition when that time comes. Israeli governments rarely complete their four-year term in office.