The conflict involving Saudi Arabia, the government of Yemen and Yemeni rebels risks being so difficult to understand and hard for reporters to cover that its importance will be lost on Americans.

A long-simmering conflict between the government of Yemen, a mostly Sunni Muslim nation, and Houthi rebels, who are Shiite Muslims, like neighboring Iran, has spilled over into Saudi Arabia, which is fundamentally Sunni. The Houthi-Yemen government struggle takes place in a context that also includes lingering separatist sentiment in what had been South Yemen, formerly known as Aden, which was united in 1990 with then-North Yemen.

The Saudis claim that the Houthi rebels attacked Saudi security elements on the Saudi side of the border. Accounts differ as to what happened next. The Saudis say their security forces routed the Houthis, while the Houthis claim that Saudi forces fled in disarray, leaving captives behind. In any case, the Saudi government then used its air force, armed in part with U.S.-supplied fighter bombers, to attack the Houthis, undoubtedly killing civilians as well, as has happened in Iraq and Afghanistan in comparable circumstances.

It has been difficult to get objective information on this mini-war. The parties are not well known for candor in such situations and the area itself is virtually inaccessible to reporters. Yesterday the United Nations Children's Fund said the Saudis evacuated dozens of villages because of fighting, while Houthi rebels said Saudi Arabia unleashed air strikes on 15 villages.

It would be easy to say that what happens between the Yemen government, Houthi rebels and Saudi air and ground forces doesn't matter to the United States, except for several factors. The first is that the Saudis' U.S.-supplied aircraft probably require U.S. technical support. That means U.S. military involvement -- even though indirect -- in the affair.

Second, given the fragility of the Saudi government, any violent conflict involving it puts its stability at risk. If, for example, the Yemeni rebels were to make life for the Saudi authorities more difficult in the border area or elsewhere in the kingdom, the repercussions could be serious.

The United States has to care because of its longtime alliance with Saudi Arabia, its high imports of Saudi oil and the kingdom's general pre-eminence in the world oil market.

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