According to figures from the U.N.'s World Health Organization, at least 944 Yemenis have been killed and nearly 3,500 injured since the Saudi-led campaign began.
The Saudis say the next phase will scale back airstrikes and focus more on providing humanitarian assistance and kick-starting a political process to reconcile Yemen's warring factions. The country's toothless government, driven out of Sanaa last year, had come to power in 2012 through a Saudi-authored transition.
It's unlikely Riyadh will have as much say a second time around. Critics, including some American officials, fear the intervention may backfire.
Here's what a month of bombing has achieved:
Rolling back the Houthi tide
The initial spur to Operation Decisive Storm was the steady advance of Houthi rebels, a Shiite political movement that receives some support from Iran, into Yemen's south last month. The airstrikes appear to have thwarted the Houthis continued takeover of key military installations in the country, particularly a few air bases pulverized by the Saudi coalition.
That may reduce threats posed by the Houthis to Saudi territory — one of the supposed justifications for the campaign. But it does little to stabilize Yemen itself, which is in the grips of continued conflict between the Houthis and southern factions arrayed against it.
The country's army has more or less dissolved, with some units allying with the Houthis. While the Saudis have mooted dispatching ground troops, no such force has been cobbled together as yet.
The hope is that a month of heavy bombardment compels the Houthis to come to the negotiating table. But openings for peace still look thin.
Houthi forces continue to encircle the southern coastal city of Aden where, until a month ago, the erstwhile Yemeni President Abed Rabbo Mansour Hadi had taken sanctuary. It's likely the Saudis will have to continue their strikes to prevent the Houthis from taking the city.
A Houthi spokesman said the Houthis would consider dialogue only after the "complete end" of Saudi "aggression against Yemen."
A looming humanitarian catastrophe
All the while, civilian casualties are mounting and what's left of the Yemeni state is on the brink of "an imminent collapse," reports the WHO, referring to the country's health care services. This is from a press release issued on Wednesday:
Health facilities are struggling to function as they face increasing shortages of life-saving medicines and vital health supplies, frequent disruptions in power supply and lack of fuel for generators. Lack of fuel has also disrupted functionality of ambulances and the delivery of health supplies across the country.Power cuts and fuel shortages also threaten to disrupt the vaccine cold chain, leaving millions of children below the age of five unvaccinated. This increases the risk of communicable diseases such as measles, which is prevalent in Yemen, as well as polio, which has been eliminated but is now at risk of reappearing.Shortages of safe water have resulted in increased risk of diarrhea, and other diseases. “Over the past 4 weeks, national disease surveillance reports show a doubling in the number of cases of bloody diarrhea in children below the age of 5, as well as an increase in the number of cases of measles and suspected malaria. High rates of malnutrition among women and children below the age of 5 have also been reported,” says Dr. Ahmed Shadoul, WHO Representative for Yemen.
Gains for al-Qaeda
Combating this wing al-Qaeda, known as AQAP, has been the primary objective of U.S. policy in Yemen for the past decade, and has involved an extensive drone operation.
A deepening polarization
Ever since Operation Decisive Storm began, experts have looked at the wider context of Saudi Arabia's regional rivalry with Iran: the former is a Sunni orthodox kingdom, the latter a Shiite theocracy; their proxies are battling in other pockets of the Middle East.
Iran's exact role in Yemen's conflict — which itself was not a sectarian battle — is a matter of debate. Its shadow in the country, as well as the heavy-handedness of the Saudi response, has led to a bitter war of words across the Middle East and worries that a spiraling crisis could trigger a larger, dangerous conflagration.
Moreover, the enmities within Yemen are hardening, with factions in Aden steeling themselves for a grim fight against the Houthis. Ironically, they're all largely united in their total disregard for Hadi, the "legitimate" president who has taken shelter in Riyadh and was powerless to prevent his country's unraveling in the preceding years.
"The strategic challenges of warfare in failed states must either address the broader reasons for those failures, or run a critical risk of becoming failed wars," writes Anthony Cordesman of the Center for Strategic and International Studies in Washington.
In the case of the Saudi intervention, so far, that risk seems rather acute.
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