Saudi Arabia has lost control of nearly all of western Yemen's Red Sea coast to a surprise Houthi offensive, a major blow to Riyadh and to global shipping through the Bab al-Mandeb strait.

• The Houthis quietly massed 100,000 fighters and pushed to the coast without Saudi or Western intelligence noticing.
• Saudi-backed Yemeni units were hollowed out, with real troop strength only 20% of what was on paper, so they fled or deserted.
• Saudi warplanes largely stayed away and Riyadh refused to send its own troops, leaving its proxies without a fallback.
• The Houthis captured American-made armored trucks and heavy ammunition stocks, hit Saudi Arabia's east-west oil pipeline, and claim to have downed a Saudi F-15.
• Pakistan, Egypt, and the U.S. all declined to intervene, and Israel is out because Riyadh won't join the Abraham Accords.

Outlook: The Houthis are expected to push next on Taiz, Marib, or Aden while demanding reparations and lifted restrictions from a Saudi Arabia that now looks more like a hostage than a regional power.