President Obama got some strongly worded advice yesterday on how to deal with Israel’s Prime Minister Bibi Netanyahu, who’ll be making his first visit to the United States as Israel’s new leader in mid-May. The Obama-Netanyahu meeting promises to be a showdown.

Zbigniew Brzezinski, the veteran strategist and hardliner — who was Jimmy Carter’s national security adviser — told a conference yesterday that in the history of US peacemaking in the Middle East, the United States has never once spelled out its own vision for what a two-state solution would look like. That, said Brzezinski, is exactly what President Obama needs to do. And fast.

Brzezinski was speaking at a conference on US-Saudi relations sponsored by the New America Foundation and Saudi Arabia’s Committee on International Trade. Brzezinski, who advised Obama early in the presidential campaign, was exiled from Obamaland after his less-than-devout support for Israel made him a liability.

“The United States has to spell out the minimum parameters of peace,” said Zbig. Perhaps in deference to the conference’s Saudi sponsors, Brzezinski said that there is an “urgent need for a US-Saudi alliance for peace in the Middle East.” Other speakers on a star-studded opening panel were Chuck Hagel, the former Republican senator from Nebraska and Prince Turki al-Faisal, who served for decades as the head of Saudi Arabia’s intelligence service.

Turki, who also served as Saudi Arabia’s ambassador to the United States, warned Obama to preempt Netanyahu, who intends to tell the president that there can’t be progress in the Israel-Palestine conflict until the United States solves the problem of Iran’s pursuit of nuclear weapons to Israel’s satisfaction. Obama, said Turki, should tell the Israeli leader: “Mr. Netanyahu, you have to listen to me first.” Rita Hauser, the veteran conservative strategist on the panel, agreed: “Netanyahu has to learn very quickly that the president means business.”

Hauser, long associated with the RAND Corporation and other thinktanks, also said bluntly that the United States is going to have to deal with Hamas, which she called a “central element” of Palestinian politics. “Hamas will control Gaza,” she said. She urged the administration to take steps to encourage the formation of a Palestinian unity government, involving Hamas and Fatah, the central pillar of the old Palestine Liberation Organization.

Obama, said Hauser, will find it politically difficult to talk to Hamas. (Translated: She means that the Israel lobby and its friends in Congress would go ballistic.) So she recommends that Washington encourage the Europeans in their dialogue with Hamas and allow Saudi Arabia to help broker a deal. (Egypt is already trying to swing a Fatah-Hamas deal.) The current chaos in Palestinian circles benefits Israel, she said, and she accused former Israeli Prime Minister Ariel Sharon of deliberately splintering the Palestinians by withdrawing from Gaza, an action that allowed Gaza to fall to Hamas.

A Hamas-Fatah accord is an important, even crucial, first step in making any progress toward an Israel-Palestine two-state solution, which Obama says he supports strongly — and which Netanyahu opposes. Getting it done won’t be easy, however. At the conference, Turki pointed out that “the popularity of Hamas skyrocketed” after the December-January invasion of Gaza by Israel. “In the eyes of the Palestinians,” he said, “Hamas came out a winner.” As a result, it might be a lot harder to convince Hamas to make concessions.

But both Saudi Arabia and Egypt, of course, are suspicious of Hamas, not only because of its radicalism but because of its ties to Iran. According to the Egyptians, who are sponsoring talks in Cairo between the two Palestinian factions, Iran is pressing Hamas to resist a deal. Writing in the Wall Street Journal today, Abdel Monem Said Ali of Egypt’s premier thinktank said:

After the war [in Gaza] ended, Egypt resumed its efforts to reach a long-term cease-fire. Iran pressured the Hamas leadership to resist. Cairo’s ongoing effort to build a Palestinian unity government, by bringing together Fatah and Hamas, has also been undermined by intense Iranian pressure on Hamas.

Obama needs to tell Netanyahu, in public or privately, that he supports a Hamas-Fatah accord and that the United States will deal with a Palestinian unity government. He needs to explain to Netanyahu that he won’t be diverted by Israel’s alarmist cries about Iran, instead maintaining the focus on the two-state solution. And, as Brzezinksi says, Obama needs to outline his vision for a deal. The world knows what it means: the removal of Israel’s illegal settlements in the West Bank, the withdrawal of Israel to its ’67 borders, the partition of Jerusalem in some fashion to allow the Palestinians to have their capital in East Jerusalem, and an equitable deal over the Palestinians right-to-return to the former Palestine, involving a hefty financial compensation to those who were forced to flee their homes in 1948 and 1967. The world knows it. Now, Obama has to say it.