At a cemetery in Sanaa, a man waters the grave of a relative reportedly killed in Yemen’s civil war. (Yahyah Arhab/EPA-EFE/Shutterstock)

U.N. envoy Martin Griffiths has engaged in shuttle diplomacy for months, repeatedly meeting the parties to the conflict in Yemen, in a bid to bring peace to a country where thousands of civilians have died and millions are at risk of starvation. Finally, he persuaded the warring sides to come to the negotiating table.

On Thursday, they are scheduled to meet in Geneva — the most serious effort in the past two years to reach a deal that could end the war, though few observers expect a significant breakthrough.

The acrimony is so great and mistrust so deep that the sides were not even expected on the eve of the gathering to meet face to face in the sessions.

“No one is really willing to give much to the other side or demonstrate too much enthusiasm for concessions,” said Stephen Seche, a former U.S. ambassador to Yemen. “They are saying, basically, we’re not even going to sit in the same room. So we are starting from a very low base.”

Yemen’s civil war, now in its fourth year, pits northern rebels known as Houthis against the internationally recognized Yemeni government of President Abed Rabbo Mansour Hadi, which is backed by a regional military coalition led by Saudi Arabia and the United Arab Emirates and supported by the United States.

As of Wednesday night, the Houthi delegation was still in the Yemeni capital of Sanaa, rebel officials said. The coalition, which controls the airspace, refused the delegation permission to fly because the Houthis wanted to take scores of their loyalists along for medical treatment. Griffiths told reporters in Geneva on Wednesdaythat he remained optimistic that both sides would be at the talks.

Martin Griffiths, U.N. special envoy for Yemen, gives a news conference Wednesday ahead of peace talks with the government and Houthi rebels in Geneva. (Fabrice Coffrini/AFP/Getty Images)

Diplomats and analysts say the Geneva meeting actually represents an enormous step forward. “Reaching that point has not been easy,” said Elizabeth Dickinson, a senior Middle East analyst with the International Crisis Group. “It’s rare that both sides feel that they are in a strong-enough position and that the other side is in a weak-enough one to come to the table.”

It also takes place as the Trump administration faces growing pressure to justify its military support for the Saudi-led coalition’s activities in Yemen. Since the beginning of the conflict in 2015, the United States has refueled coalition aircraft, provided intelligence and sold weapons to the Saudis.

The sides last met in Kuwait in 2016 to discuss a political settlement, but those talks broke down acrimoniously. This time, the tensions — and the stakes — are much higher.

The United Nations declared this year that the humanitarian crisis in Yemen was the most severe in the world. Three-quarters of its 28 million people are in need of assistance, and more than 3 million have fled their homes. Civilian casualties from the conflict have exceeded 17,000, the United Nations says, and continue to rise. A downward economic spiral and soaring inflation have deepened poverty and suffocated even the middle class.

The Houthis, widely said to be backed by Iran, now routinely fire ballistic missiles into Saudi Arabia. The coalition, in turn, has ratcheted up the pressure on the rebels by laying siege to the strategic port city of Hodeida, restricting imports and choking off funds used to pay salaries in Houthi areas.

The Trump administration is due to report to Congress next week on the coalition’s efforts to protect civilians. A new law links continued U.S. refueling of coalition aircraft to efforts by Saudi Arabia and the UAE to minimize civilian casualties.

Griffiths said it was time for the two sides to begin a dialogue after two years away from the negotiating table. “This is an opportunity this week for that page to be turned, and that corner to be turned,” he told reporters in Geneva.

He was careful about raising expectations, describing the gathering, which is expected to last three to four days, as “consultations” and “not formal negotiations.”

“The best we can hope for in the short term is some kind of confidence-building measures, small gains that help pave the way for more serious negotiations down the road,” said Gerald Feierstein, another former U.S. ambassador to Yemen.

Those measures, for instance, could include a prisoner exchange and steps to carry out vaccinations in areas that have been inaccessible due to fighting.

The Saudi-led coalition launched its offensive against Hodeida in the spring, aiming to put pressure on the Houthis to accept a political solution, analysts said. But the coalition failed to capture the city.

The Houthis, said Seche, “have not lost any ground” and now “don’t have any particular reason to consider concessions.”

On Tuesday, Sen. Chris Murphy (D-Conn.), one of most outspoken congressional critics of U.S. involvement in the conflict, called on the administration to put more pressure on Saudi Arabia and its allies to embrace Griffiths’s efforts at brokering a deal. International criticism against the coalition is growing as its airstrikes have killed thousands of Yemeni civilians, including at least 40 children in an Aug. 9 attack on a school bus.

“Of course, the United States has enormous leverage; we may have total, complete leverage,” Murphy said in an interview. “The fact that we don’t use it, the fact that we allow for the civilian death toll to spiral, is unconscionable.”

Robert Malley, who worked on Middle East issues at the Obama White House, said the Trump administration should use its rapport with Persian Gulf countries to push for a change of course in Yemen. “The best way for Saudi Arabia and the UAE to respond to those concerns would be for them to agree to a cease-fire, and push the Hadi government — which wholly depends on their support — to show real flexibility in peace talks,” said Malley, who is now president of the International Crisis Group.