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Ringing question

By Lester Holt, NBC News Anchor

Good day from New York. Brian is taking the night off and I'll be sitting in tonight.

When my phone rings at 3 a.m., my first thought is, something awful has happened. If I'm lucky, it's just a wrong number. It's safe to assume wrong numbers aren't put through to the President of the United States, and so a middle of the night call to the commander-in-chief can't be good. That's the premise of a new Hillary Clinton ad airing in Texas, that has been getting plenty of airing on the cable news channels today as a point of political discussion.

The ad says, "It's 3 a.m. and your children are safe and asleep. But there's a phone in the White House and it's ringing. Something's happening in the world. Your vote will decide who answers that call."

The camera then shows Hillary Clinton picking up the phone. The spot, and its not-too-subtle implication that Senator Clinton is better qualified to handle a national security crisis, brought a quick response from Barack Obama. Tonight on Nightly News, NBC's Andrea Mitchell will show the ad, Obama's response, and report on the the tightening race in Texas as well as Ohio.

Word that a man found in a Las Vegas hotel today was suffering from ricin poising set off quite a few alarms today. Ricin is an especially deadly poison that is lethal even in tiny amounts, and has no known antidote. While there are a lot of blanks to be filled in on this story, the word from Las Vegas authorities is that this does not appear to be foul play, and there is no apparent connection to terrorism. So what's it all about? Our George Lewis is working the story and will have much more on tonight's newscast.

Erin Burnett from CNBC will stop by this evening to help us put today's Wall Street slide into perspective. The S&P 500 lost 3 percent and the Dow and Nasdaq each shed 2.75 percent.

We'll have those stories, as well as one woman's long held secret that shatters a commonly held assumption about eating disorders, on the Friday edition of NBC Nightly News.