The Saudi coalition is closing in on the rebel Houthi movement, moving steadily up from the southern port of Aden, where 2,800 Saudi and United Arab Emirates troops are alleged to have landed along with soldiers loyal to President Abdu Rabbu Mansour Hadi, in early August. These forces not only took Aden back from the Houthis, but have conquered five southern provinces and are now besieging the country’s third-largest city, Taiz. The months of heavy Saudi and coalition airstrikes, some of them appearing to target civilians, and of heavy fighting between Hadi forces and the Houthis, have left a swath of destruction across the already desperate country that bodes ill for the future of the region.

The Houthi movement, based among the Zaidi Shiite minority in Yemen and allied with deposed former president Ali Abdullah Saleh, clearly bit off more than it could chew when it attempted to take over the whole country this winter and spring. Although the Houthis marched into the capital of Sana last September, they initially cohabited with the elected government of President Hadi. But in January, the Houthis made a definitive coup, and Hadi and many members of his government fled the northern capital of Sana.

Their alliance with elements of the Yemeni military still loyal to Saleh and access to the country’s military weapons depots gave the Houthis some initial tactical advantages, allowing them to move south and take Sunni cities such as Taiz and Aden this spring. But it was never very likely that the Yemeni Sunni majority would accept Houthi rule, especially in the south, where Sunnis predominate, and the mobilized youth who had overthrown Saleh during the 2011–12 Arab Spring protests were dismayed at the idea of a tribal, fundamentalist coup.

Most consequential of all, the Houthi takeover alarmed the incoming government of King Salman in Saudi Arabia, who acceded in January on the death of his more cautious half-brother, King Abdullah. A hawk obsessed with the threat of encirclement by Iran, Salman decided to launch the first major Saudi war since King Abdel Aziz Ibn Saud conquered the Hejaz in 1924–26.

Although the Houthis are routinely called “Iran-backed,” they are an indigenous movement pushing back against Wahhabi and Salafi hard-line Sunni incursions into Zaidi Shiite regions like Saada. They have probably received a few million dollars in aid from Iran, but that is peanuts. Most of their weapons are American, captured from army depots after the collapse of the Yemeni military in September of 2014. The Saudis and the United Arab Emirates, however, see the Houthi takeover of Yemen during the past year as a plot hatched in Tehran to extend Shiite soft power in the Middle East. In fact, the Zaidi branch of Islam is not very close to Iranian Shiism, lacks ayatollahs, and has often been seen as straddling the Sunni-Shiite divide.

From the late 1960s, Yemen was two countries, a communist south and a nationalist north. In 1990, with the fall of the Eastern Bloc in Europe, the two unified, though strong southern secessionist sentiments remained. Unified Yemen began spiraling out of control in about 2004, when the Houthi movement began rebelling in Saada in protest against well-funded Saudi Wahhabi proselytizing of Zaidi Shiites. At the same time, in some regions of the south, insurgent Sunnis influenced by Wahhabis, called Salafis, had gravitated to Al Qaeda. The president for life, Ali Abdullah Saleh, who came to power as a left-leaning nationalist in 1978, proved unable to put down these rebellions. In 2011–12, he faced a third movement against his government, that of rebellious youth and reformists who demanded more democracy, accountability, and better economic management, and which forced Saleh to step down.

Saleh’s vice president, Hadi, was elected president in a nationwide referendum in February of 2012 and all-too-slow preparations were made for new parliamentary elections. The political process, however, collapsed when the Houthis marched into Sana last September, apparently with the collusion of military units loyal to the deposed Saleh.

The military conquests of the Houthis to the south of the capital in March through this summer may have been aimed at forestalling an easy military riposte by Hadi and his Gulf allies by denying them the port of Aden. The Zaidi religious militia heavily bombarded the Sunni population centers it conquered, showing reckless disregard for civilian life.

At the same time, Saudi Arabia and allies such as the UAE and even Morocco heavily bombarded weapons and fuel depots in order to weaken the Houthi forces and the rump Yemeni military units loyal to Saleh. In some instances they appear to have targeted civilian areas such as historic downtown Sana or the city of Mokha. Likewise, Saada and its hinterlands, the far northern region that is the birthplace of the Houthi movement, has been virtually reduced to rubble. When challenged by international human rights organizations over these violations of the laws of war, Saudi spokesmen have typically denied the allegations and blamed the destruction on Houthi artillery (which has also been reckless and destructive).

The Gulf coalition also imposed a debilitating blockade on Yemen, with horrible consequences for civilians. Nor were the Houthis exactly very interested in the welfare of civilians. Electricity has been knocked out in some regions of the country, and fuel depots have been blown up. Ports such as Aden and Hodeida have suffered extensive damage, whether from artillery barrages by Houthis or from aerial bombardment by the Saudi coalition. Since March, humanitarian agencies estimate, at least 4,000 have been killed, over 20,000 wounded, and 1.2 million displaced, in a country of 24 million. Half the population is now suffering from hunger, and there are widespread water shortages from a long-term drought, exacerbated by climate change, that is causing a die-off of farm animals in some regions. Some 6 million people are on the verge of famine.

The controversy over the heavy and sometimes apparently indiscriminate bombing of Houthi-held territory by Saudi Arabia and its allies has touched the United States, which has provided 45 intelligence personnel to the war effort, advising on tactics and targets. The United States maintains that it does not plan individual bombing runs.

The Saudi forces supporting a restoration of the Hadi government have had the momentum this month, though they have been better at expelling the Houthis than at restoring order to the southern provinces they have liberated. Analysts also find it worrisome that Al Qaeda in the Arabian Peninsula has expanded its control of some southern regions, aided by central government collapse. Whether that genie can soon be put back in the bottle is unclear. The fate of the north also hangs in the balance. Zaidis are a third of Yemenis, predominating in the north of the country, though not all Zaidis support or agree with the Houthis. It is not clear that they can accept a Saudi-imposed government, any more than the Sunnis and socialists of Aden could accept a Zaidi one.

Whether Yemen can come back together as a country depends very much on whether the Saudi invasion is aimed at returning President Hadi and his reformist prime minister and now vice president, Khalid Bahah, to power, or whether an attempt will be made to impose Saudi Wahhabism on Yemen (something probably not acceptable to either the Sunnis or the Zaidi Shiites). If Bahah can return to power, the Purdue-educated former ambassador to the United Nations, who supported the 2011 youth movement against Saleh, may have a chance of restoring order and legitimacy. The sooner parliamentary elections can be held, the better, though the disarray of the country makes this step a distant prospect. With over a million displaced and an economy in shambles, the likelihood of Yemen returning to stability any time soon is low. The big question is whether the continued tumult in that country will spill over, affecting the security of neighboring countries and of the Red Sea (a key international trade route) itself.