MITCHELL: In our polling today, in our NBC News survey, Monkey Online poll, there's an eight-point spread. Hillary Clinton is leading Donald Trump, but single digits, and not a big wave behind her, also in her NBC News-Wall Street Journal poll. So this could be a very close race. How long are you going to wait before you make a decision about endorsement? Will you decide before -- ?

SANDERS: I think -- you're asking, I think, with all due respect, Andrea, the wrong question. It's not a question of my endorsement. It's a question of the American people understanding that Secretary Clinton is prepared to stand with them as they work longer hours for low wages, as they cannot afford health care, as their kids can't afford to go to college. Make it clear that she is on their side, that she is prepared to take on Wall Street, the drug companies, fossil fuel industry. Deal with the global crisis of climate change. I have no doubt that if Secretary Clinton makes that position, those positions clear, she will defeat Trump and defeat him by a very wide margin.