Former foreign minister Alexander Downer argues US President Donald Trump must "put boots on the ground" and seize control of the Strait of Hormuz if America wants to achieve its objectives in Iran. “I think he has to do more than that; he has to prosecute this war till the end, not stop and start,” Mr Downer told News24 host Chris Kenny. “I’m sorry to say this, but I think they will have to put boots on the ground and seize control of the Strait of Hormuz. “I don’t think the Americans can achieve their objectives just from the air.”