For months, US Secretary of State John Kerry has cut a rather lonely figure in Washington, openly mocked for his single-minded pursuit of what many believe is a fool's errand -- a Middle East peace deal.

The kindest critics have given him an "A" for effort, while remaining skeptical that he can achieve something that has eluded American presidents for decades.

Others have derided his efforts as a lost cause from the start, and one pundit even cruelly dubbed him "the lone ranger."

So Kerry can be forgiven the smile of satisfaction that crossed his face on the way home from Amman late Friday after announcing a tentative deal for Israelis and Palestinians to resume talks, perhaps as soon as this week.

Staff applauded as he bounded onto his plane, grabbed a bottle of beer, and kicked back for the first time after four days of nail-biting drama, which almost saw his hopes for a resumption of talks slip away.

After months of dogged diplomacy and six intensive trips to the region, he has achieved what his predecessor Hillary Clinton never even tried to do -- convincing the two sides to agree to return to the negotiating table.

And while he knows the hard work is just beginning and he risks very public and humiliating failure given how far apart the two sides are, he can bask briefly in his first success as America's top diplomat.

As the public face of US foreign policy, it's a welcome bright spot for an administration under fire abroad for refusing to do more to end the Syrian conflict and seen as preoccupied with domestic concerns.

And while the skeptics are already warning of doom and gloom, the climate this time around might be more nurturing for some kind of a breakthrough.

On the personal front, Kerry is reveling in his new job, apparently having foregone any further presidential ambitions, which might have kept him from wading into one of the world's most intractable conflicts.

And it appears the White House has given him carte blanche in an area in which President Barack Obama doesn't want to expend any more energy.

Obama was badly bitten when his own much vaunted 2010 foray into Middle East peace collapsed in a matter of weeks leading to the stalemate which -- if all goes according to plan -- Kerry has now unlocked.

The regional landscape has also changed, with the Arab Spring triggering upheaval in many of Israel's neighbors, raising fears in the Jewish state that hostile groups could end up seizing power.

Analysts have long argued that the Palestinian-Israeli conflict remains the festering sore fuelling discontent in the Arab world, and that only a peace deal can guarantee Israel's long-term security.

Israel is also facing increasing international isolation over the Palestinians' plight. At the United Nations in December, only nine nations voted against giving the Palestinians upgraded statehood, with 138 in favor.

An EU ban on funding Jewish settlements, adopted last week as Kerry was in Amman, may also have helped push Israel back to the negotiations.

Israeli Prime Minister Benjamin Netanyahu was furious at the vote, which he told Kerry was "damaging efforts to restart the talks."

But it may also have served as yet another warning that the current status quo is no longer sustainable.

Just hours before Kerry announced the breakthrough at a hastily gathered press event at Queen Alia airport in Amman, he flew on Jordanian helicopters to the West Bank headquarters of Palestinian president Mahmud Abbas in Ramallah.

After shaking hands to seal the deal, Kerry and his staff and travelling press corps took off again just as dusk was falling.

As the Sabbath began for Israelis, Palestinians were gathering for the traditional iftar feast to break a long day of fasting in the holy month of Ramadan.

Flying low over the Holy Land with the sky turning purple, the divisions which have soaked the territory in blood over the decades were hard to discern.

Below was a landscape sparsely dotted with villages and towns, where two peoples were quietly observing their religious traditions.

"The representatives of two proud people today have decided that the difficult road ahead is worth traveling and that the daunting challenges that we face are worth tackling," Kerry told reporters.

Through sheer force of will, the lone ranger seems to have defied the odds so far, but the road ahead is long and full of pitfalls. And the outcome remains far from certain.