SF professor on debate preparations, candidates' differing styles

American voters will see Hillary Clinton and Donald Trump side-by-side for the first time Monday night when they face off at Hofstra University in New York for the first of three presidential debates.

The stakes are high, with as many as 20% of voters saying they are still undecided.

The two candidate's political styles are sharp contrasts, down to the way they're preparing for the debate.

Donald Trump is continuing to campaign, greeting voters Thursday at a cheesesteak shop in Philadelphia.

Fans greeted the Republican candidate, shouting out "We love you Donald."

Hillary Clinton, the more traditional politician, is taking a traditional approach, studying briefing books at home with a circle of advisors, according to campaign staff.

"She has been off the campaign trail for a good point the last few days and simply studying him and trying to figure out pressure points," said University of San Francisco political science professor James Taylor.

Taylor says while Clinton is an experienced debater, she faces a challenge in figuring out how to balance policy points while scoring points for personal likeability. She also has the challenge of preparing to debate an untested opponent who made his mark in the crowded Republican primary with one liners, not policy proclamations.

"Donald Trump did not clearly devastate Marco Rubio or Ted Cruz, or any of those guys in terms of a full 90-minute debate performance. What he did was won sound bites that carried the news cycle the next day," said Taylor.

In preparation, Trump has reached out to his supporters with a questionnaire asking questions such as what topics they'd like him to address in the debate, whether he should refer to Hillary Clinton as "Crooked Hillary", and whether they feel his campaign is too conservative or too liberal.

Taylor says Trump must go beyond preaching to his choir, however, and show substance on policy if he wants to sway the swing state voters.

"He's going to have to try and contain himself and at the same time be sharp on the questions and issues and also figure out emotionally when to push the right buttons to affect Hillary Clinton," Taylor said.

The debate will be moderated by NBC's Lester Holt, who announced that the questions will be focused on three topics: America's direction, Achieving prosperity, and Securing America.