In a softball interview with MSNBC’s Chris Matthews, Democratic Party frontrunner Hillary Clinton vehemently denied she’s a socialist, but found herself unable to answer what the difference is between a Democrat and a socialist.

Clinton’s main rival for the Democratic Party’s presidential nomination is Vermont senator and self-proclaimed democratic socialist Bernie Sanders.

Matthews asked Clinton, “What’s the difference between a socialist and a Democrat? Is that a question you want to answer, or would you rather not?”

“You’d have to ask [Sanders],” Clinton said before being interrupted by Matthews.

“You see, I’m asking you. You’re a Democrat, he’s a socialist. Would you like someone to call you a socialist?” Matthews asked.

“I am not one,” Hillary responded without answering the question.

“OK, well what’s the difference between a socialist and a Democrat?” Matthews asked again.

[dcquiz] “I can tell you what I am, I am a progressive Democrat,” Clinton responded.

“How is that different than a socialist?” Matthews asked a third time.

“I am a progressive Democrat who likes to get things done,” Clinton continued. “And who believes we’re better off in this country when we’re trying to solve problems together. Getting people to work together. There will always be strong feelings and I respect that, from, you know, the far right, the far left, libertarians, whoever it might be, but we need to get people working together. We’ve got to get the economy fixed, get all of our problems, you know, really tackled and that’s what I want to do.”

Clinton joins Democratic Party Chairwoman Debbie Wasserman Schultz in being unable to explain the difference between a Democrat and a socialist.