President Donald Trump’s strong support for Prime Minister Benjamin Netanyahu in his reelection campaign underscored the close alliance between the two leaders. On numerous issues, they have similar outlooks, have coordinated closely, and have defined their nation’s security, as well as their political fortunes, as being very much intertwined.

While the coalition negotiations are still ahead, it is clear that Netanyahu will continue in office, making continued smooth coordination between the two governments likely. Even so, some challenging decisions still lie ahead for both of them.

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No American administration and Israeli government, no matter how close, are always one hundred percent aligned, as demonstrated by Trump’s surprise announcement of the withdrawal of U.S. troops from Syria late last year.

On three major issues, decisions await that could test the close coordination between these two allies.

First, the administration has to decide whether and when to present its plan for "the deal of the century," for Israeli-Palestinian peace, as well as the content of the plan.

Already, the timetable is slipping. After initial indications that the plan would be presented shortly after the Israeli elections, the administration is now signaling that it is more likely to wait until after the Israeli coalition is formed, and the Passover and Ramadan holidays have passed. That takes us to June, at the earliest.

At the same time, the substance of the plan is coming into greater focus. In a series of recent statements, Secretary of State Mike Pompeo has revealed more and more about the thinking behind the administration’s still-secret plan.

Open gallery view Israeli PM Benjamin Netanyahu holds a proclamation signed by U.S. President Donald Trump recognizing Israel's sovereignty over the Golan during the weekly cabinet meeting. Jerusalem, April 14, 2019 Credit: Ronen Zvulun,AP

He has signaled clearly that the plan will not be based on the formula of two states for two peoples, can accommodate Israeli moves to annex West Bank settlements, and will seek to substitute economic benefits for Palestinians - funded by the Arab Gulf states - for fulfilling their political aspirations for statehood.

But a question hangs over this decision for both governments. Such a plan is likely to be rejected by the Palestinians (in fairness, they would reject almost any plan proposed by Trump), by Arab states (who continue to back the two-state idea), by Europe and Russia, and by Democratic presidential candidates in the United States. The latter group will likely make clear that they will not feel bound by such a proposal, and will plan to return to the traditional U.S. position in support of two states in 2021.

So can such a plan be viably implemented, or - if it fails - could Israel proceed with unilateral annexation moves, at acceptable costs in such an environment?

One of those costs could be in U.S. and Israeli relations with Arab states, which presents the second issue for decision. Saudi, UAE, and other Gulf state leaders have made clear their appreciation for Trump’s strong stand against Iran. They are also closely aligned with Israel on the issue, have permitted a range of gestures of normalization, and deemphasized the Palestinian issue’s importance.

But they have not yet been asked to lend public support for a U.S. plan that buries any hopes of Palestinian statehood, much less fund it. They have not yet been asked to look the other way at overt Israeli moves, with U.S. backing, to annex portions of the West Bank. They have not yet been asked to accept U.S. and Israeli positions that their key Arab allies - Jordan and Egypt - fear could be destabilizing.

The signs of this tension are growing. King Abdullah of Jordan recently complained to Members of Congress that he is completely in the dark about the political elements of the Trump plan, but worried by what he smells is coming. Egyptian President Abdelfattah al-Sisi followed up last week’s warm Oval Office meeting with Trump with an announcement that Egypt would not participate in the American plan for a unified Arab military force - dubbed the "Arab NATO."

Open gallery view Jordan's King Abdullah II meeting with Egypt's President Abdel Fattah al-Sisi at the presidential palace in Cairo. March 24, 2019 Credit: AFP

So the question raised here is: can Israel’s warming ties with Arab states, and can those Arab states’ partnerships with the United States, withstand the presentation of a Trump plan that seeks to kill all possibilities for two states? Are the gains in those relationships truly irreversible, or could they be squandered?

Finally, on Iran, the administration faces a critical decision as time in Trump’s first term winds down: will they take some more definitive action to set back the Iranian nuclear program?

The steps so far - withdrawing from the Iran nuclear deal and increasing sanctions - have won support from Israel and Arab Gulf states, and have imposed considerable economic pain on Iran. But Iran has remained in the nuclear deal, and appears to be trying to wait Trump out.

In the little more than year and a half that Trump can be sure he has left, and barely a year before he will be fully engaged in his reelection campaign, at least some of his advisers will argue that he must do more. The administration this week floated an argument that the Authorization for the Use of Military Force (AUMF) passed by Congress in 2001 after the 9/11 attacks can apply to strikes on Iran nearly two decades later.

With some Democratic presidential candidates voicing support for the United States returning to the Iran nuclear deal if they are victorious, Trump’s Middle East allies may also hope for a more definitive blow to Iran’s nuclear program during his first term.

Open gallery view President Donald Trump and first lady Melania Trump greet members of the U.S. military at a hangar rally at Al Asad Air Base, Iraq. Dec. 26, 2018 Credit: Andrew Harnik,AP

But that alignment of interests may not extend to who should strike such a blow. And that could flip the decision back on them.

Is Trump, who campaigned fiercely against the U.S. war in Iraq and has been in a hurry to get U.S. troops out of Syria, prepared to start a new war in the region, just as he goes back to the voters? And if not, Israel and its Arab partners may face their own decision when Trump informs them that they have an American green light to act.

That is not a decision that Netanyahu or any Arab leader has ever faced, but it is time that they give serious thought to how they would respond.

Daniel B. Shapiro is Distinguished Visiting Fellow at the Institute for National Security Studies in Tel Aviv. He served as U.S. Ambassador to Israel, and Senior Director for the Middle East and North Africa in the Obama Administration. Twitter: @DanielBShapiro