Democratic presidential candidate Hillary Clinton took aim at Donald Trump Thursday with some of her harshest criticism to date. Speaking in San Diego ahead of Tuesday’s California primary, Clinton said electing Trump would be a “historic mistake.”

Hillary Clinton: “This is not someone who should ever have the nuclear codes, because it’s not hard to imagine Donald Trump leading us into a war just because somebody got under his very thin skin.”

Trump responded by blasting Clinton’s decision to “stupidly raise her hand” for the Iraq War.