Saudi Ambassador to the United States Adel al-Jubeir has announced that his country has begun military operations against Yemen, with an eye toward restoring Gen. Abd-Rabbu Mansour Hadi as the “legitimate government.”

Reports are that the military action has begun with airstrikes, which Saudi officials insist are being conducted only by Saudi warplanes and not with any coordination with any other country, against the Houthi forces.

The Houthis have controlled the Yemeni capital for months and hold much of the territory along the west coast of Yemen. They have also been advancing into the area around Aden.

The Saudis object the the Shi’ite Houthis, against whom they have fought multiple border skirmishes in recent years. US officials say that in addition to the warplanes, the Saudis have been building up heavy forces along the Yemeni border.

Yemen was heading in the direction of a multi-faction civil war at any rate, with Hadi’s forces increasingly confined to the south, the Houthis spanning the north and west, al-Qaeda in the tribal areas, and ISIS and the forces of previous dictator Ali Abdullah Saleh both roaming around as well. Now, the Saudis are in the mix.

Obviously the Saudis’ goal is to install a friendly government, and to that end they’re seeing Gen. Hadi, “elected” in a single-candidate vote in 2012, as having at least a little legitimacy. Hadi’s resignation and subsequent fleeing into exile, however, are going to make it awfully hard for the Saudis to reassert him as a credible ruler.

Hadi had been courting the Saudis as a backer, claiming the Houthis were backed by Iran, Saudi Arabia’s regional rival. While there was limited evidence of Iran backing the Houthis before, they almost certainly will at this point, just to counter the Saudi incursion.