Robert F. Kennedy Jr., President Donald Trump’s pick to lead the top U.S. health agency, came under attack at a Senate confirmation hearing on Wednesday, with Democratic lawmakers accusing him of covering up his anti-vaccine views and embracing conspiracy theories to dissuade use of lifesaving medicines. Massachusetts Sen. Elizabeth Warren and Kennedy got into a heated shouting match when she asked him to make a promise in front of the hearing. “I’m asking you right now that you will not take a financial stake in every one of the lawsuits [against pharmaceutical companies] so that what you do as secretary will also benefit you financially down the line,” Warren asked. “Senator, you’re asking me not to sue pharmaceutical companies,” Kennedy replied prompting Warren to sternly fire back, “No, I am not!”