Wallace on Clinton: She Is Democratic ‘Head Candidate, But Not the Heart Candidate’

Democratic debate 2015: What to expect from the first clash (NBC News)

The first Democratic presidential debate includes plenty of potential landmines for front-runner Hillary Clinton, says political commentator Nicolle Wallace.

"I feel nervous for Hillary Clinton," she said Tuesday in an interview with TODAY'S Savannah Guthrie.

"She's in the same position, the unenviable position, of being the Democratic head candidate, but not the heart candidate," Wallace said. "Once again somebody else has captured the passion of the Democratic party."

In 2008, it was then-Illinois Sen. Barack Obama who seized the party faithful's imagination and passion. This time, it's her most competitive rival, Vermont Sen. Bernie Sanders.

"If she makes this mistake again of not capturing the passion the way Bernie Sanders has, she'll only have herself to blame," Wallace said.

Tuesday night's debate in Las Vegas will provide Sanders with his broadest exposure to date on a national stage.

Sanders said he will not get personal during the event but he already has called out Clinton for veering to the left politically on environmental, trade and Wall Street issues, suggesting she has flip-flopped on previous stances.