The new U.S. administration’s policy to end the war in Yemen represents an important milestone in the six-year conflict. President Joe Biden has announced the end of U.S. support for the military operations of the Saudi-led coalition and a more active U.S. role in efforts to end the country’s war. In light of this, he has appointed Timothy Lenderking, a former deputy assistant secretary of state, as his special envoy to Yemen.

However, it remains unclear how the United States will be able to push the Iranian-backed Ansar Allah, better known as the Houthis, to enter into a peace deal. This is also a key challenge facing the United Nations special envoy to Yemen, Martin Griffiths, and it will continue to hinder peace efforts. The Houthis’ priority today is to make more gains, not to engage in power-sharing deals. The group’s purported willingness to make peace appears to be only a tactical step.

The Houthis have benefited from the U.S. policy changes in three ways. First, these represent a victory for the Houthis by undermining the interests of its leading adversaries. The Saudi-led coalition entered the war in 2015 with ten countries. Today, Saudi Arabia finds itself alone. Second, the Houthis will benefit from the accompanying diplomacy of the United States. This coincides with the reversal of the U.S. designation of the Houthis as a foreign terrorist organization, as this would have impeded the mission of the U.S. special envoy.

And third, the Houthis will likely accelerate the pace of the war to take advantage of the fact that the Saudis will probably decrease their military operations because of the suspension of U.S. air support. This will create an incentive for the Houthis to expand in the Yemeni interior, into areas bordering where the group is now deployed. This includes Yemen’s west coast, Ma’rib, Jawf, and Shabwa, among other areas. It’s notable that following the U.S. decisions, the Houthis resumed their attacks on Ma’rib, a governorate that hosts more than 2 million internally displaced persons and where the human rights situation is deteriorating. Many areas will probably face similar Houthi attacks in the coming weeks.

There are several major challenges for reaching a peace agreement. First, the Houthis have no motivation to join a political process and share power with other Yemeni parties, given that today they control most areas in northern Yemen. Based on their vision of a solution, the Houthis are trying to position themselves as the country’s sole representatives. They do not want to engage in a process that would deny them a dominant role in internal Yemeni affairs.

This trend has been reinforced by the dynamics that have taken place in the past few years, which have favored the Houthis. The anti-Houthi coalition in general has been deeply divided, with its members and local allies often working at cross-purposes. This has greatly weakened, among others, the internationally recognized Yemeni government of President ‘Abd Rabbo Mansour Hadi. Consequently, the Houthis have had no reason to accept agreements that they signed in the past, such as the Peace and National Partnership Agreement of September 2014. The Houthi approach is reinforced by an ideological conviction that they must reestablish the Zaydi Imamate, which was replaced by a republic in 1962, and that bestows on them a right to govern Yemen.

A second challenge is the Houthis’ growing military capabilities, which make the group much less likely to embrace the compromises that a settlement would entail. The capture of Yemeni military stocks by the Houthis at the end of 2014 allowed them to engage in large-scale military action. The fact that Iran has also supplied them with advanced weapons, like the Houthis’ ability to recruit extensively in the areas under their control, has hardened a perception that the group has no real need to surrender anything.

There is also a structural problem in the Houthi movement. It views itself as a military entity rather than a political movement. The Houthis seem to be convinced that arms bring greater gains than negotiations. The balance of power may prove them right. There appears to be no force in Yemen today that can deter the Houthis as the policies pursued by Saudi Arabia and the United Arab Emirates, as well as the infighting among Yemeni factions, have encouraged the group to be ambitious. The Saudi-backed Hadi government, for example, has been at bitter odds with the UAE-backed Southern Transitional Council, while the Houthis remain strong and unified. In such a context, it makes little sense for the group to pursue peace negotiations when it can simply divide and conquer.

A third challenge is that those who want to push the Houthis into peace talks have few means of pressure to do so. As a nonstate entity, the Houthis are indifferent to international sanctions or criticism. The UN special envoy is trying to talk to Iranian officials and make use of their leverage with the Houthis. However, Tehran’s influence over the group is inseparable from its broader interests in Yemen and the region. Therefore, what is required to end the conflict cannot be separated from the course of U.S.-Iranian talks, if they occur.

It is important to also underline that the Iranian wing in the Houthi movement has increasingly becoming the dominant one in the last three years. Therefore, any solution in Yemen will almost certainly be linked to Iran’s multiple agendas in the region. Not surprisingly perhaps, the task of persuading the Houthis to give up its military track and negotiate a political resolution is somewhat reminiscent of the efforts to persuade Iran to abandon its nuclear program.

All this does not mean that the Houthis will not engage in peace talks. On the contrary, they may pursue negotiations while maintaining the momentum of their military actions on the ground. This has been the Houthi approach since 2014. Following the Stockholm Agreement, which helped to contain the battles in the coastal city of Hodeida, battles continued to rage in northern Yemen.

In wanting to encourage the Houthis to engage in negotiations, many international actors have condoned their systematic attacks against their domestic opponents. Yet rather than enhance the chances of a settlement, such actions have made the situation worse, exacerbating the humanitarian situation. In this environment the possibility of a peace agreement has diminished, making the task of the United Nations and United States envoys extremely difficult.