US intelligence agencies and private experts say that Russia is probably responsible for major cyber attacks on the American political system. But, in tonight’s debate, Republican nominee Donald Trump—who has been accused of cozying up to Russia—said that “no one knows” who committed the attacks. He said they could even have been done by “someone who weighs 400 pounds who is sitting on a bed.”

Trump made his remark after his Democrat opponent, Hillary Clinton suggested that, as president, she might order a massive cyber attack on Russia if it does not stop its cyber-intrusions on the US. It is a step that president Barack Obama has not said he would do. But, Clinton said, “We have to make clear that the United States has much greater capacity,” hinting at general agreement by experts that the US is the global leader in cyber technology.

In his response, Trump cast doubt on US cyber capability. “We should be better,” he said. He went on to cast doubt as well on who committed the cyber break-ins. “No one knows it was Russia,” he said. “It could be China. Or it could be someone who weighs 400 pounds who is sitting on a bed. We don’t know.”