The world, especially Israel, has once again been surprised by the latest expression of the Arab Spring.

On Sunday, thousands of unarmed Palestinian refugees living in Syria, Lebanon, and Jordan tried to cross the military borders of Israel. They were attempting to enter land that earlier Palestinians had been forced to flee, either during the 1948 creation of modern Israel or during the 1967 Arab-Israeli War.

Most of the protesters were peaceful, although some resorted to intifada-style stone throwing. Israeli security forces were caught off guard. The result was that several Palestinians were killed and dozens were injured.

The protests were timed for the anniversary of Israel’s founding, or as Arabs call it, Youm an-Nakba, “the Day of the Catastrophe.”But the surprise popular uprising also came as the entire Israeli-Palestinian struggle appears headed for a very different phase.

The peace process is broken, as best seen in the resignation last week of President Obama’s special envoy for peace, former Sen. George Mitchell. Palestinian leaders have lost faith in the United States as a mediator and plan to ask the UN General Assembly to recognize a Palestine state this September.

And on Friday, Israeli Prime Minister Benjamin Netanyahu speaks before Congress, another example of how he has politically outflanked Mr. Obama and the US attempt to end the expansion of Jewish settlements on the West Bank.

Now, with the Arab Spring at Israel’s doorstep, the dynamics of the Middle East are changing fast.

Many of the roughly 700,000 Palestinian refugees living in Arab states see the potential to use peaceful means to return to their ancestral land, tapping social-networking tools such as Facebook to organize protests such as Sunday’s march to the Israeli borders.

But there’s one problem. They must stay true to the two basic principles of the Arab Spring, best expressed in Egypt’s revolution: the use of nonviolent tactics and the idea that democracy should rise above religious or ethnic differences.

As much as the organizers of the May 15 march tried to keep it peaceful, they couldn’t contain those who hurled stones at Israeli soldiers. And in their goal of reclaiming Israeli-controlled land, they failed to address the question of whether they want to create a democratic state in which Jews and Arabs (Palestinians) will live together.

Despite those issues, more such protests are likely. Israeli Defense Minister Ehud Barak warned this “may only be the beginning” of a new kind of nonviolent struggle between Israel and the Palestinians. “The danger is that more mass processions like these will appear, not necessarily near the border, but also other places,” he said in a television interview. Or, as Israeli Intelligence Minister Dan Meridor said in a TV interview: “There is a change here and we haven’t internalized it.”

Israel itself has not come to grips with whether it is a Jewish state with an Arab minority or a secular democracy. That question is even more troublesome the longer Israel retains control over the growing Palestinian population on the West Bank.

Universal values such as democracy and nonviolence as expressed in the Arab uprisings are now challenging both Palestinians and Israelis in coming to terms with each other.

Israel may be forced to finally settle the question of its identity as a home for the Jewish diaspora but one based on secular democracy. The Palestinian diaspora, too, must decide what kind of democratic statehood they want on land where Israeli Jews have lived for decades.

And both sides can make a firm commitment to use nonviolent means in any confrontations.

The spirit of the Arab Spring has created a new narrative for Israelis and Palestinians. Rather than assert their respective religious or ethnic rights to a land they both once lived in largely peacefully, they should use this moment in history to unite around the principles of democracy and peace. The protesters in Cairo’s Tahrir Square were able to do it.