Former President Bill Clinton yesterday looked back 40 years to the landmark federal commission that investigated urban riots in the 1960s and warned that persistent racial discrimination "leaves in its wake a quieter riot of disillusion and despair."

In his keynote address at "Kerner Plus 40," a University of Pennsylvania-hosted symposium on the legacy of the 1968 National Advisory Commission on Civil Disorder (known as the Kerner Commission because its chairman was Illinois Gov. Otto Kerner), Clinton said the "dramatic increase in diversity" inside government and industry "has helped us move toward one America" - but that racial inequality persists.

"I wouldn't spend five minutes celebrating the progress," said Clinton, "not with all that we have to do."

In its most famous finding, the 11-member commission created by President Lyndon B. Johnson said, "Our nation is moving toward two societies, one black, one white - separate and unequal."

For many black Americans circa 1968, noted Clinton, the nation wasn't just moving that way, it was already there. They lived in decaying ghettos with little hope of social or economic advancement.

Speaking before 1,200 students and faculty inside ornately painted Irvine Auditorium, Clinton said his eyes were reopened to inequality in America when he worked on relief efforts after Hurricane Katrina.

In a prosperous nation, he said, he saw in New Orleans "thousands of brothers and sisters smothering in an airtight cage of poverty."

While applauding the "rise of the black middle class," a development that seemed "inconceivable" when he was growing up, Clinton said the relevant question today is: "What is life like for people who will never run for government, or be TV stars, or movie stars?" What is it like for the many black Americans who - 40 years after Kerner - still are three times more likely than whites to live in poverty?

With his wife in a do-or-die phase of her run for the presidency, the former president also campaigned for her.

En route from the airport to Penn, Clinton dropped by the Penrose Diner in South Philadelphia to pose with patrons for photos, autograph napkins and promote Hillary Clinton's campaign.

As he walked in around 10 a.m., waitress Denise D'Ambro exclaimed: "South Philly is all for Hillary!"

Clinton took a cup of coffee; he did not sit but kept moving.

"This looks like a good breakfast place," he said, chitchatting and shaking hands. He also entertained a serious question.

Waitress Susan Borman asked about his wife's health-care plan.

"How is she going to do it? How is she going to fund it?"

Clinton, charmingly wonkish, took about 10 minutes to go into detail about her situation, and how it would work for everyone.

Just a few minutes later, he was out the door and on his way to Penn.

Following his keynote address, Clinton met privately with about 60 of Hillary Clinton's most prominent supporters in Pennsylvania.

The meeting, held inside Penn's Houston Hall, served to rally the faithful and "energize them" for the work to be done ahead of April's primary, said Mark Nevins, Pennsylvania communications director for the Clinton campaign.

Among those there were Gov. Rendell, Mayor Nutter, former Mayor John F. Street, state Democratic Party Chairman T.J. Rooney, local NAACP head J. Whyatt Mondesire and other high-profile supporters.

The president's message was that things were going well in Texas and Ohio, where his wife faces two key primary battles on Tuesday, Nevins said.

"If we deliver a convincing win in Pennsylvania, she'll end up being the nominee," Nevins said, quoting the former president.

In an interview, Nutter, who has endorsed Hillary Clinton, said he spoke with the former president.

"He's been a friend for some time and is always tremendously gracious," Nutter said. "There is a significant amount of enthusiasm and anticipation about Pennsylvania being a major player in the Democratic presidential primary, which has not been the case since 1992."

Nutter said he vowed to "do everything I can, anything I can, and whatever they might ask me to do to be fully supportive."

Rendell and Nutter reiterated their support for Hillary Clinton - no matter how she does in Ohio and Texas - at a news conference yesterday morning on economic development at the Greater Philadelphia Chamber of Commerce in Center City before leaving for the meeting with Bill Clinton.

In a separate interview, Rendell said he doesn't think Clinton would quit the race if she loses in Ohio and Texas.

Losses would, however, take away "one of the central arguments of the campaign," that she has carried all the big states.

"I think you'll find the campaign will take a good, hard look on Wednesday morning if they lose," Rendell said.