Former President Bill Clinton isn't on the ballot, but since he joined the campaign trail last month some of her rivals see him as fair game.

Republican frontrunner Donald Trump invoked his infidelity and attacked his "terrible record of women abuse" while Vermont Sen. Bernie Sanders, her top Democratic challenger, called his behavior "totally disgraceful and unacceptable."

At Sunday's debate in Charleston, the last Democratic showdown before ballots are cast in Iowa on Feb. 1, Clinton revealed in detail what role her husband, as the nation's first "First Gentleman," would play in her administration.

"It'll start at the kitchen table. We'll see how it goes from there," Clinton opened, as the audience chuckled.

She continued:

"I'm going to ask for his ideas, I'm going ask for his advice, and I'm going use him as a goodwill emissary to go around the country to find the best ideas we've got, because I do believe, as he said, everything that's wrong with America has been solved somewhere in America."

Sanders, in his response, to an attack on Hillary Clinton's ties to Wall Street. But he was asked by moderator Andrea Mitchell whether he regretted his comments about the former president.

Said Sanders:

"That question annoys me. I cannot walk down the street - Secretary Clinton knows this - without being told how much I have to attack Secretary Clinton ... I've avoided doing that, trying to run an issues oriented question."

He was pressed again on why he chose to answer it that way.

If I don't answer it, there's another front-page story. Yes, and I mean this seriously. His behavior was deplorable ... I'm going to debate Secretary Clinton and Gov. [Martin] O'Malley on the issues facing the American people, not Bill Clinton's personal behavior."