A friend who does not follow the Middle East with the masochistic intensity some of us do, casually hit me with a daunting request. "One of these days," she said, "you'll have to explain to me this whole thing with Jerusalem."

I sighed.

Where do you begin to explain a dispute over a city that's more than 5,000 years old? Do you start with Abraham, or with King Solomon and King David? Or do you jump to the Crusades, to Salahadin? Do I talk about Jesus? About Muslim beliefs? Which empires should I mention: Persian, Roman, Ottoman, British?

Or, do I relate that for thousands of years, the Jewish people, dispersed around the world, have ended their Passover meal with the cry "Next Year in Jerusalem!"? Maybe I should begin explaining that Palestinians claim the eastern side, with its large Muslim population, as the capital of their future state, but most Israelis consider Jerusalem "undivided" as their country's "eternal capital."

In Jerusalem, as in much of this history-soaked region, nothing is more real, more palpable and more powerful, than the past. Perhaps, then, the best place to start is the future.

Instead of arguing about what part of the past matters most, we should focus on the future most people say they want. A majority of Israelis and Palestinians say they want to see peace, with two states living side by side. That, in the most contentious sliver of the world, is a delicate point of agreement that must be carefully nurtured, particularly because it remains a matter of passionate disagreement for minorities on both sides.

Given that Jerusalem is the most emotional of all issues dividing Israelis and Palestinians, it is truly baffling why President Obama has — for the second time in his administration — tangled up the possibility of peace in the most difficult of all problems.

The current crisis began when Israeli housing officials approved one of many steps in previously announced building plans for East Jerusalem during a visit by Vice President Joe Biden. That, as I wrote then, was a terrible mistake. Israeli officials apologized profusely. But Washington seems reluctant to let the matter go, again raising its demands on Israel to a level never done even by Palestinians.

I am convinced that Israelis will negotiate the fate of Jerusalem at the bargaining table. But demanding that an Israeli prime minister ban Jews from building in part of Jerusalem as a condition for talks simply creates more problems.

Jerusalem and the rest of the West Bank will become contentious issues when the time comes to make decisions. It's too soon now to turn them into obstacles.

Obama did this before. As a result, Israelis and Palestinians haven't spoken in more than a year. Last year, Obama demanded that Israel stop all settlement construction in the West Bank. Palestinians, who had negotiated before, suddenly refused to meet with Israelis unless they did that. Palestinians had never made that a precondition for negotiations. Palestinian Authority President Mahmoud Abbas told the German magazine Spiegel, "In his speech to the Islamic world in Cairo, (Obama) called for a complete freeze on settlements. When the American president does this, I cannot accept anything less."

Middle East diplomacy requires enormous sensitivity. Jerusalem is the fault line in 5,000 years of emotionally charged history. That means the megaphone should be used sparingly, and the pressure should be reserved for times when it really serves a useful purpose.

Obama has successfully managed to place all the blame for the current impasse on Israel, whose government undoubtedly has made serious mistakes. The truth, however, is that for the second time in his presidency, Obama has managed to set back the prospects for Middle East peace.