There is abundant evidence that the high civilian death toll in Yemen is the result of deliberate — not accidental — strikes by Saudi Arabia. During its air campaign, Saudi Arabia has bombed endless civilian targets — including homes, farms, markets, factories, water infrastructure, hospitals, and children's schools — and has even gone so far as to use internationally banned cluster weapons, which are designed to inflict damage over a wide area and often remain lethal years after being dropped.

But when secretary of state nominee and former Exxon CEO Rex Tillerson was asked about Saudi Arabia's use of cluster weapons during his confirmation hearing Wednesday, he declined to answer, and suggested that the way to discourage Saudi Arabia from hitting civilians in Yemen is to provide them with additional targeting intelligence.