During his nearly three years in office, President Obama has tried a new type of American leadership in the Middle East, one that is more moral than muscular, less unilaterally assertive and more humbly collaborative.

While he’s been mostly successful and consistent, all that may now be viewed in the region as meaningless if the United States effectively vetoes a request by the Palestinians for the United Nations Security Council to recognize their homeland as a state.

Palestinian leaders admit that their bid for UN recognition won’t create a state but may at least bring some parity with Israel in any negotiations. It will also provide symbolic hope for their despondent people, who are witnessing the dawn of liberty in other Arab lands.

Nonetheless, an Obama veto at the UN will be seen as a slap to those Palestinian aspirations. And it would allow Arabs to confirm their view that Israel commands a tight hold on American politicians through domestic lobbies and campaign money.

Once the veto is cast, the president must then try to restore his style of moral leadership. Anticipating that difficult task, Mr. Obama used his speech Wednesday before the UN General Assembly to remind the world of his plans to withdraw troops from Iraq and Afghanistan, his role in ousting Muammar Qaddafi and continuing support for Libya, and his actions to further help the Arab Spring’s drive for democracy.

“More individuals are claiming their universal right to live in freedom and dignity,” he stated.

It is now the obvious lack of freedom for Israel (to be secure) and for the Palestinians (to run their own country) that must be the president’s focus. And indeed, the Palestinian bid has forced Obama and other world leaders to renew efforts for talks – which is one positive outcome of the Palestinians’ bid for statehood.

Just a year ago, Obama’s speech to the UN included a call for a Palestine state. Now his credibility is at stake in the Middle East. He could help both sides in any talks by being more specific on the details of the compromises needed to achieve long-lasting peace, and gain big-power support for his plans

Palestinians still welcome US mediation between them and Israel, despite their UN bid. A specific US plan would help each side more easily persuade its people to support a final deal against attacks by their respective extremists.

Gen. David Petraeus, who is now CIA chief, has said that the Israeli-Palestinian conflict has helped foment anti-American sentiment in the region “due to a perception of US favoritism for Israel.”

With that perception reinforced by the expected US veto at the UN, Obama’s promised brand of moral leadership needs a rebirth.