Although the Iranian-backed Houthi rebels in Yemen claimed responsibility for last week’s attack on Saudi Arabia’s Abqaiq oil processing plant, the audacious operation looks like the handiwork of the Islamic Republic of Iran. It is even emerging that the drones or cruise missiles were fired directly from Iranian soil.

Stirrings of war are on the horizon. President Donald Trump warned that a US response is “locked and loaded” and the Saudi King and Crown Prince are not best pleased.

For years, Shia Iran and Sunni Saudi Arabia have engaged in a proxy conflict. Currently, the regional rivals support different sides in the civil wars in Syria and Yemen. But why would Iran instigate a direct attack against Saudi Arabia and risk conflict not only with Riyadh, but possibly the United States as well? The attack seems especially irrational considering the timing. Just days earlier there was credible talk about a potential meeting between Trump and his Iranian counterpart Hassan Rouhani at the United Nations. Meanwhile, Trump fired his hawkish national security advisor John Bolton, indicating a willingness to ease some sanctions.

Perhaps Iran wanted revenge against Riyadh’s involvement in Yemen, a civil war that has claimed 90,000 lives, including tens of thousands of civilians, and caused widespread misery, poverty and disease? However, if Iran  figured that disrupting Saudi Arabia’s oil revenues would push the Kingdom to retreat from Yemen, it was a serious miscalculation.