JERUSALEM — When Prime Minister Netanyahu said that not only he but all of Israel was praying for Jordanian King Hussein's recovery from cancer of the lymph nodes, Netanyahu might have been exaggerating for effect — but not by much.

Hussein is by far the most popular — if not the only popular — Arab leader in the eyes of Israelis. Only the slain Egyptian leader Anwar Sadat might have eclipsed Hussein's popularity here. The Jordanian king is well-spoken of by the Israeli right, left and center — even by those who don't hide their hatred of Yasser Arafat and their mistrust of outspoken anti-Netanyahu leaders like Egyptian President Hosni Mubarak.

Now Hussein, 62, who has ruled his country since he was 17 years old, is in danger. Doctors at the Mayo Clinic in Rochester, Minn., where Hussein is being treated, say he will have to continue treatment there for as long as five months. The king's heir is his 50-year-old brother, Prince Hassan.

Jordan is the most stable Arab country, and the friendliest to Israel. What will it mean if there is a change in power in the kingdom? Oded Granot, a diplomatic correspondent for the Ma'ariv daily, notes that Hassan is also a moderate political figure and that an orderly transfer of power would be expected.

"But Prince Hassan is not as popular as Hussein, and he would have to work much harder to pull Jordan out of its economic and governmental crises. Hassan would also have to work especially hard to convince the Jordanian people that they must continue the peace process with Israel, even though Israel is continually at odds with the Palestinians," Granot said.

Jordan is a poor country. Its people have not tasted the "fruits of peace" economic prosperity that they were told to expect as a result of the 1994 peace agreement with Israel.

The government opposition is dominated by the Moslem Brotherhood, which is intimately connected to Hamas. Most of Jordan's intellectual class has always been overtly anti-Israeli, even during the Rabin-Peres years, and their sentiments have reached a new pitch during the Netanyahu regime.

Hussein was crowned after an Arab in Jerusalem assassinated his grandfather, King Abdallah, for taking a relatively peaceful approach to the new Jewish state.

If and when he ascends to the throne, Prince Hassan will have his hands full maintaining the stability that his brother has managed for nearly a half-century.

Hussein wasn't always an Israeli favorite. Acting on overly optimistic advice from then-Egyptian leader Gamal Abdel Nasser, he attacked Jerusalem during the Six-Day War in 1967 and lost the West Bank, including East Jerusalem, for his trouble. As a result, the Jordanian monarch was lumped together in the Israeli view as part of a broad Arab front that only wanted to push the Jews into the sea.

But beginning with Golda Meir in the early 1970s, Hussein began meeting clandestinely with Israeli leaders, and became known as the most moderate of Arab heads of state. Despite his public statements, he is considered more of a rival than a supporter of Arafat and the Palestinian leadership. The Palestine Liberation Organization tried to overthrow Hussein in "Black September" of 1970, but Hussein won out in a bitter, bloody struggle.

King Hussein's support for Saddam Hussein in the Gulf War was a matter not of choice but of necessity. Saddam's million-man army threatened Jordan on its eastern border. The Jordanian masses were intoxicated with Saddam; opposing the Iraqi leader might have led Jordanians to revolt. In the end, Saddam was humbled and King Hussein was left standing.

"The secret of [the king's] success is his personality — a combination of great charm and tremendous ability to improvise and read the mood of the street," Granot said.

Hussein won the hearts of Israelis during the signing of the peace accord in Washington, when he and his wife, Queen Noor, the former Lisa Halaby of Philadelphia, cried openly during the moving speech by Yitzhak Rabin. He won their hearts again two years later, when he came to Israel and sat on the floor alongside the families mourning their seven children who had been murdered by a Jordanian soldier.

For the last three decades, Hussein has put Israel's mind at ease about its eastern border, and maybe even taught Israelis a few lessons in grace, humility and warmth.

It may be going too far to say all Israelis are praying for his recovery. But most are certainly hoping for it.