'Big victory on the Wall', tweeted Donald Trump as the US Supreme Court allowed him to use $2.5bn of defence funds for building a section of the wall along the Mexico border. The top court overruled an order by a California court that had stopped the Trump from using the money to build a wall in California, Arizona and New Mexico. In February this year, the US President declared a national emergency so that his border wall project could be funded with Congress' approval.