Yemen’s Southern Secessionists on the March

The rapid expansion of the separatist Southern Transitional Council (STC) in Yemen is moving the balance of power and may lead to a redrawing of the map.

Forces aligned with the STC, which is headquartered in Aden on the southwestern coast of Yemen, reached the country’s eastern border with Oman on December 4. The move consolidates STC control over the territories that constituted the state of South Yemen, or the People’s Democratic Republic of Yemen, until the country’s unification in 1990. The STC, which participates in Yemen’s official government while effectively controlling much of the south of the country, argues for southern secession.

The STC is amplifying sit-ins arranged by local leaders in governorates across southern Yemen online, including the areas where STC forces recently took control, demanding the south declare itself to be the state of South Yemen, also termed South Arabia by the STC. While the STC has not shared plans to announce secession immediately, they are laying the groundwork for a future declaration.

Fractured Yemeni Government Has Struggled To Find Unity

The Internationally Recognized Government of Yemen (IRG) is headed by the Presidential Leadership Council (PLC), an eight-man body with members from several factions. This includes STC President Aidarous al-Zubaidi, and other STC-aligned, pro-secession, southern leaders who serve alongside pro-unity northern politicians and tribal leaders, including members of al-Islah, a big-tent party home to Yemen’s branch of the Muslim Brotherhood. The many bickering factions within the PLC have rendered the government largely unable to meet the needs of the people or the demands of fighting the Houthis in Yemen’s decade-long civil war. The Houthis are an Iran-backed, U.S.-designated foreign terrorist organization that effectively rules much of northern Yemen.

Yemen is also an arena for competing Gulf interests. The United Arab Emirates (UAE) has supported the STC and its partners, whereas Saudi Arabia has backed a range of political and tribal factions inside and outside of the government. There is deep distrust between many parties, including between players like the UAE and its southern partners and al-Islah, which have come together only in the face of Houthi threats.

A realignment of the spheres of influence not only impacts Yemeni actors, but also their Gulf sponsors. Saudi Arabia, eager to ensure quiet from their southern border, is now in discussions with the Houthis over their escalating rhetoric and demands for financial compensation. The Saudis’ declining influence in the resource-rich east, after the STC’s expansion, means they can only leverage a shrinking sphere of influence. 

Southern Forces Argue They Will Make Yemen Safer

While the expansion of the STC’s control shifts the balance of power, STC leaders insist their motivation for this advance was security, not a consolidation of power. Houthi and al-Qaeda in the Arabian Peninsula (AQAP) smugglers have operated in eastern Yemen for years and even al-Shabaab — a terrorist group based in Somalia — has established a presence, as highlighted in the 2025 report by the UN Panel of Experts on Yemen. The STC argues that the forces previously in control of these eastern territories, many of which are government affiliated, were “the lifeline through which the Houthis, the Muslim Brotherhood, and other terrorist organisations breathed,” thus necessitating intervention.

American Diplomacy Can Support Unity To Fight the Houthis

The official U.S. position is support for one Yemen and its governing bodies including the PLC. However, Washington should engage with all parties as the southern forces are essential partners in the fight against the Iran-backed Houthis and in countering AQAP. Furthermore, the Trump administration should encourage both Saudi Arabia and the UAE to prioritize stability in Yemen and to maintain focus on the fight against the Houthis. To that end, the STC should proceed slowly, avoiding unilateral action that may spark conflict in the anti-Houthi coalition.

In the meantime, if the STC hopes to one day have an independent South Yemen recognized by the international community, the best course of action it can take now is to follow through on promises of strong counterterrorism and counter-smuggling efforts to stabilize and strengthen the area under its control.

Bridget Toomey is a research analyst at the Foundation for Defense of Democracies (FDD). For more analysis from Bridget and FDD, please subscribe HERE. Follow Bridget on X @BridgetKToomey. Follow FDD on X @FDD. FDD is a Washington, DC-based, nonpartisan research institute focusing on national security and foreign policy.