Las Vegas–Democratic presidential candidate Martin O’Malley took a swipe at Republican Donald Trump on Wednesday by standing with employees who are trying to organize a union at the billionaire’s hotel in Las Vegas. “There are a couple of things Donald Trump doesn’t understand,” O’Malley said, according to Politico. “If we want our economy to grow, we need to treat our workers with dignity and respect, pay them better and respect their right to organize.”