The stage is set ahead of what could be the most watched, and consequential, presidential debate in history. Donald Trump and Hillary Clinton will go one on one Monday night and Josh Robin has a preview from Hofstra University in Hempstead, New York.

Rudy Giuliani was one member of the Republican team at Hofstra on Sunday night preparing for Monday's showdown. 

They're making sure all is as perfect as can be before the candidates themselves settle in behind the podiums —before they're beamed out to tens of millions of people. 

"I think they both have a challenge," said Frank Fahrenkopf, Jr. the co-chairman of the Commission on Presidential Debates. "For Hillary she has to show that she's got warmth, personality. That she's likeable. For Donald, I think he's got a show that he's presidential. People have got to look at his man and say he could be president. "

During the debate, there will be a third person on stage. 

The moderator, Lester Holt of NBC News. 

 He's pressed to fact check on the fly, especially Trump, who is collecting a string of falsehoods. 

"Hillary should be given some time to actually talk about what she wants to do to make a difference in people's lives," said Clinton Campaign Manager Robby Mook. "She shouldn't have to spend the whole debate correcting the record." 

But the co-chairman of the debate commission says that's not the moderator's job. 

"A moderator in a debate is a facilitator," Fahrenkopf said. "So if I say something that's wrong the other candidate should be the one who is correcting me."

Trump is said to be preparing with less of a traditional exercise. Reportedly, there have been no fake podium set ups, for instance.

We talked with Giuliani on Sunday morning. 

"We’ve been spending a lot of time preparing for it the way Donald Trump likes to prepare for it, which is a much more loose, much more relaxed way than the way it seems the compulsive way in which Hillary Clinton is preparing," Giuliani said.

Even as they prepared for Monday's big night, both candidates on Sunday squeezed in some time for an important foreign leader. 

Benjamin Netanyahu was at the United Nations last week. 

Foreign affairs could be just one flash point Monday. 

Observers say Trump may have an advantage going in, if expectations for him are lower than his opponent.