US president Donald Trump just threatened to bomb Oman, a US ally. Increasingly humiliated by his failing war against Iran, Trump has become more and more erratic. Oman was mediating the last US-Iran deal which Trump broke in February under pressure from Israel. Trump was waffling about a potential Pakistan-brokered peace deal with Iran when he made the bizarre threat. Tehran has said it wants Oman to help impose tolls on a re-opened Strait of Hormuz, a vital energy corridor. Trump, whose attack predictably led to the strait being closed in the first place, had a little tantrum about the idea:…