WASHINGTON -- A group of protesters managed to penetrate the Hillary Clinton campaign bubble and the result was a far more spirited exchange than normally seen at a stage-managed political event.

Activists from the Black Lives Matter movement have disrupted other Democratic presidential candidates' events to demand more attention to race-related issues like the deaths of unarmed people in confrontations with police.

But they'd failed to puncture the imposing protective circle around the former first lady and secretary of state, who travels with a Secret Service detail.

When they were shut out of an event last week, they managed to get a closed-door meeting with the Democratic front-runner. It produced a blunt back-and-forth about race relations, criminal justice reform and political strategy.

The activists began by blaming Clinton and her husband for promoting tough-on-crime reforms in the 1990s that led to skyrocketing incarceration rates, broken families and poorer communities.

"You and your family have been in no uncertain way partially responsible for this," said Julius Jones, one of the members of Black Lives Matter's Boston chapter.

"Now that you understand the consequences, what in your heart has changed?"

Clinton expressed sympathy with the protesters but chided them over their tactics. Someone captured that New Hampshire encounter last week on video, which was later sent to Good magazine and published this week on the web.

Clinton has in fact admitted that some of the 1990s policies were a mistake. A 1994 law she campaigned for shifted billions from public housing to federal prisons, ramped up drug penalties and heralded a near-doubling of the U.S.'s highest-in-the-world prison population in less than a decade.

She's now called for an end to that era of mass incarceration. In an April speech on justice reform, she proposed body cameras in every police department, less military-style equipment for local forces and a loosening of some drug penalties.

Clinton said the activists need to articulate their own goals.

She said older movements like civil rights, women's liberation and gay rights only succeeded after their leaders identified specific targets -- like which laws they wanted to overturn.

"There has to be some positive vision, and plan, that can move people toward," Clinton told the protesters.

"Once you say, 'You know, this country has still not recovered from its original sin (of slavery),' which is true -- once you say that, then the next question by people who are on the sidelines, which is the vast majority of Americans, the next question is, 'Well, what do you want me to do about it? What am I supposed to do about it?'

"That's what I'm trying to put together, in a way that I can explain it and I can sell it. Because in politics, if you can't explain it and you can't sell it, it stays on the shelf."

Jones retorted that's unfair -- it's putting the onus on black people to articulate solutions for white racism: "This is, and always has been, a white problem of violence. There's not much that we can do to stop the violence against us."

That prompted a cutting rejoinder from Clinton.

"Respectfully, if that is your position, then I will talk only to white people about how we are going to deal with very real problems," she replied.

Clinton added: "You can get lip service from as many white people as you can pack into Yankee Stadium and a million more like it who are going to say, 'We get it, we get it. We are going to be nicer."'

"If that's all that happens, we'll be back here in 10 years having the same conversation. Because we will not have all of the changes that you deserve to see happen."

The conversation ended politely, albeit inconclusively. After about 15 minutes, they exchanged thank-yous and parted ways. Clinton said she was ready to do her part.

On Tuesday, she got a standing ovation at a partisan event when she criticized Republicans for failing to make a single reference to Black Lives Matter in their recent presidential primary debate.

But the protesters said they wanted more.

"What we were looking for from Secretary Clinton was a personal reflection on her responsibility for being part of the cause of this problem that we have today with mass-incarceration," Daunasia Yancey told MSNBC.

"So her response really targeting our policy wasn't sufficient for us."