While Iran has supplied missiles to the Houthis, including some that have been fired at Saudi cities, Yemen analysts say the war is principally driven by the violent factionalism that wracked Yemen in the aftermath of the Arab Spring protests of 2011.

Analyst cautioned that the talks, which are to take place in a renovated castle outside Stockholm, have at best a moderate chance of success. “If we take past as precedent, and the situation on the ground, all indicators point toward not much coming out of the talks and a resumption of fighting in Hudaydah,” said Peter Salisbury, a Yemen expert at the International Crisis Group. “I’m sorry to say that the broad momentum is very much in favor of continued violence and a worsening of the humanitarian situation, not in an outbreak of peace.”

The last peace effort collapsed in September when Houthi officials failed to turn up for talks in Geneva. This time, the Houthis have turned up at the venue first, with the government delegation expected to be led by Mr. Hadi’s foreign minister, Khaled Alyemany.

The other difference is a more concerted international focus. In Washington, pressure to bring the war to an end has been driven of late by congressional anger over the killing of the Saudi dissident Jamal Khashoggi in Turkey. Intense scrutiny of the role of Prince Mohammed, now the Saudi crown prince, has drawn attention to what critics call his reckless conduct of the war in Yemen, where thousands of civilians have died in airstrikes by Saudi and other coalition warplanes.

Last week, the United States Senate delivered a rebuke to President Trump over his policy in Yemen by supporting a resolution that seeks to end American support for the war. More debate on the same resolution is expected this week. The C.I.A. director, Gina Haspel, briefed Democratic and Republican leaders on Tuesday about the death of Mr. Khashoggi.

Houthis and Saudi officials have stressed that the talks in Sweden, if they start, will not involve negotiations to end the war, focusing instead on confidence-building measures. They are expected to discuss prisoner exchanges brokered by the Red Cross, the status of Hudaydah, and proposals to reopen Sana’s international airport, which is currently accessible only to humanitarian flights.