Since the ascension to the throne of King Salman bin Abdul-Aziz Al Saud in 2015 and the rise of his son Mohammed bin Salman first as defense minister and then as crown prince, the kingdom’s foreign policy has faced difficult choices in a fraught region. With rare exceptions the Saudis have lurched from one poor decision to the next; the Canada caper is the latest. The erratic diplomacy is hurting the kingdom.

The first tough decision of the new leadership is still their worst, to intervene in the Yemeni civil war. Worried that Iran was set to take over Yemen, the new, inexperienced Saudi leadership panicked. The Zaydi Shiite Houthis were on the doorstep of taking Aden, the last major city out of their control. Operation Decisive Storm turned into the world’s worst humanitarian catastrophe of our times. The Saudi bombing of a school bus this week is symptomatic of the Saudi coalition’s difficulties in avoiding civilian casualties in launching airstrikes against targets in a poor, backward country.

Two American presidents have colluded in the war, providing political and military support for the Saudi coalition — a black mark on our country. So has the United Kingdom. The war has no end in sight, and the total collapse of the poorest nation in the Arab world is an increasingly likely outcome, according to the United Nations.

The blockade of Qatar was also intended to produce a quick Saudi victory. The Qatari emir was excommunicated from Wahhabi Islam and was then to be deposed. As in Yemen, the Saudi leadership had no concept of how to implement its decision; Riyadh and its allies had a goal but no serious scheme to achieve it. Some reliable evidence suggest that they were planning a military invasion of Qatar but US Secretary of State Rex Tillerson vetoed the plan (probably without President Donald Trump’s knowledge).