Trump pulled back from US air strikes on Yemen's Houthis at the last minute, a relief for anyone worried about another US war, but a blow to Saudi Arabia, which is losing badly and begged for help.

• Saudi Crown Prince Mohammed bin Salman called Trump last Thursday pleading for US military help as Houthi forces advance and hit Saudi targets, including the Riyadh airport and the East-West oil pipeline.
• Trump had told advisers he had no interest in striking, then reversed and ordered the Pentagon to prepare air strikes, then reversed again by Sunday and called them off.
• The pullback came with target lists approved and bombs already being loaded onto US warplanes.
• Trump has a side deal with the Houthis: they leave US and non-Saudi ships alone in the Red Sea chokepoint, and the US leaves them alone.
• Last year's eight-week US bombing campaign burned through a billion dollars of munitions in the first month, lost two fighter jets off a carrier, and failed, which is why Trump quit after two months.
• The Saudi-backed ground coalition is a patchwork of rival Yemeni groups, some tied to ISIS and al-Qaeda, that fight each other more than the Houthis despite hundreds of billions in US-bought weapons.

Outlook: The strikes are only delayed, not cancelled, and Trump could still reverse course again under Saudi pressure, while the Houthis keep rebuilding and pushing the US to burn through its already-thin munitions stockpiles.