Among his many campaign promises, Donald Trump pledged to fix America’s crumbling roads and bridges with $1 trillion in infrastructure spending. Almost seven months into office, though, and two months removed from his vaunted “infrastructure week,” the president has revealed few details for how to pay for it. As his advisers look for ideas, a group of Australian politicians and executives has been lobbying for the administration to adopt a controversial policy of selling or leasing airports, toll roads, and other public facilities to raise money for infrastructure projects.