In ordering the killing of Major-General Qassem Soleimani, considered the second-most powerful man in Iran after Ayatollah Ali Khamenei, United States President Donald Trump has gone where his predecessors hesitated to tread. The drone strike he authorised killed the celebrated Quds Force commander as he left Baghdad Airport in Iraq while on a routine visit, and in plain sight. Mr Trump has since said that the move was intended to stop, not start, a war. Nevertheless, it will not escape notice that the last time the US killed a major military leader of note outside his home country was when the aircraft carrying Japan's Admiral Isoroku Yamamoto was shot down during World War II. The world now awaits the consequences of the US' latest action. Iran has announced it is withdrawing from the nuclear agreement it signed with world powers in 2015. Iraq's Parliament has also voted to order US troops out of the country.

No one thinks of the Iranian regime as being babes in the woods. Shi'ite-majority Iran aspires to be the Middle East's pre-eminent power. This collides with the interests of predominantly Sunni Saudi Arabia's aspirations for regional dominance. Teheran has backed its interests with a welter of overt and covert capabilities. The US, which is tied to Saudi Arabia, sees the Iranian regime as lethal, corrupt and prone to employing violent means, chiefly at the direction of Maj-Gen Soleimani. This is why some have drawn parallels with the US action against the Islamic State in Iraq and Syria's Abu Bakr al-Baghdadi, who killed himself during an October raid by US special forces.