It seems to be the question Democratic Party figureheads don’t want to answer: What’s the difference between a Democrat and a socialist?

Hillary Clinton, in an otherwise friendly interview on MSNBC, struggled to answer that question Tuesday when asked by host Chris Matthews.

At first, the Democratic presidential front-runner seemed to suggest the question should be directed at her rival in the race, Vermont Sen. Bernie Sanders, a self-described democratic socialist.

“You see, I’m asking you,” Matthews countered.

Clinton simply replied, “I’m not one.”

Beyond that, she declined to explain the differences between the two.

See the Fox News 2016 battleground prediction map and make your own election projections. See Predictions Map →

“I can tell you what I am, I am a progressive Democrat … who likes to get things done,” Clinton said. “And who believes that 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, we need to get people working together.”

The awkward exchange was reminiscent of an interview the same host had in July with Democratic National Committee Chairwoman Debbie Wasserman Schultz, who also struggled to explain the Democrat-socialist distinction.

Clinton and Schultz’ reluctance to answer the question could reflect a reluctance to rile the millions of Democrats supporting Sanders’ socialist-tinged campaign.

Matthews spoke to this undercurrent in the interview Tuesday, saying he understands Clinton wants to keep the left and center-left united.

Despite conservative charges of socialism against the Obama administration, there are still significant differences between the policies espoused by the Democratic Party and the massive welfare programs enacted in social democracies in places like Scandinavia.

But Clinton’s interview nevertheless fueled allegations that the distinctions are narrowing. “It is obvious Secretary Clinton didn’t want to get into the differences between a Democrat and a socialist, and the reason is simple: there aren’t any,” Jeff Bechdel, spokesman for the conservative America Rising PAC, said in a statement.