Republican front-runner Donald Trump has broken just about every rule of conventional US presidential campaigning. Short on a long-term political vision to help shape the destiny of the nation, he has gleefully insulted Muslims, Mexicans, women and virtually all of his opponents. A Trump-in-the-White-House scenario poses high stakes for the Gulf region. Gulf Arabs could pull billion in investment money from the US if Trump, who triggered a global outrage when he advocated a temporary ban on all Muslims entering the US, wins the presidency later this year, prominent UAE businessman Khalaf al-Habtoor said. Saudi billionaire Prince Alwaleed bin Talal,...