Valerie Green-Thomas sees them every day in her classes at the Bronx middle school where she is a special education teacher. Kids hungry, anxious, living in the dark because the electricity in their homes has been turned off.

“I really wanted to come to this country, but I am so disappointed,” she said in her Jamaican accent. “To realize that the dream is not the dream.”

Green-Thomas was one of several thousand who rallied and marched Saturday as a prelude to Sunday’s belated dedication of the Martin Luther King Jr. National Memorial. The message of the “Jobs and Justice” event, organized by the Rev. Al Sharpton’s National Action Network along with labor and civil rights groups, was that today’s poor, unemployed and homeless embody King’s unfinished business.

Before the march to the King memorial on a radiant fall afternoon, they packed the lawn at the foot of the Washington Monument, near the Sylvan Theater, carrying signs that read “I AM A MAN” and “The rich must pay their fair share.” They demanded passage of President Obama’s $447 billion American Jobs Act. The legislation was blocked in the Senate last week.

“I’m not sure why the Republican Party has become such a mean and vicious entity in this country,” said Michael Chambers of Upper Marlboro. “People need to know — we’ve got to take to the streets, make our voices heard, turn out in sufficient numbers to get attention. If we don’t, all the things we have taken for granted will be put to the wayside. There won’t be a middle class when these folks are through — there will only be rich and poor.”

Others came to offer personal testimony of the jobs-starved economy. Peggy Jackson, 55, said she has spent three years looking for work in Detroit. “America is hurting,” she said.

A burly, 40-ish man from Maryland who would give his name only as John, leaned on a cane and explained that he recently found work 18 months after being laid off. He said something has to change.

“I don’t think we’ll get the politicians to change their minds,” he said. “But I’m hoping we can get voters to change their minds about the politicians” and vote them out of office.

A succession of speakers, including American Federation of Teachers President Randi Weingarten and Labor Secretary Hilda L. Solis, offered support. They warmed up the crowd for Sharpton, whose raspy voice rang out, “No justice? No peace!” as the crowd shouted along with him, over and over.

A woman stomped her feet in the grass, and people pumped their fists.

Referring to Congress, Sharpton said, “If you won’t get the jobs bill done in the suite, we will get the jobs bill done in the street!”

Of political leaders fighting and cutting social programs, he warned, “This is not about Obama,” he boomed, “this is about my mama!”

People laughed and repeated, “It’s about my mama! That’s right!”

Like the King Memorial dedication, the march was originally scheduled for the weekend of Aug. 27 but was postponed as Hurricane Irene barreled toward the mid-Atlantic region. Toward midday Saturday, two other marches made their way through downtown Washington and linked up with “Jobs and Justice”: one in support of District voting rights — also postponed in August — and the other a contingent from Occupy D.C. There were cheers when they arrived.

“It’s about Wall Street versus Main Street,” said Jo-Lynn Gilliam, who traveled from Atlanta for the march. “Us American taxpayers, we can bail out businesses, but they can’t do anything for us?”

Before leading the voting rights marchers to the Mall, Mayor Vincent C. Gray (D) kicked off the protest at Freedom Plaza, where some protesters affiliated with Occupy D.C. are encamped. He urged the crowd of more than 1,000 to join him in becoming more outspoken about securing a voting member of Congress or achieving statehood.

“I am sick and tired of paying taxes to a nation whose leaders treat me with disdain,” said Gray, who also is scheduled to speak at Sunday’s formal unveiling of the King Memorial. “I am sick and tired of telling our children to risk their lives for the freedom of far-away nations and then come to disrespect and nullification.”

Several D.C. Council members as well as Del. Eleanor Holmes Norton (D-D.C.), Rep. John Lewis (D-Ga.) and consumer activist Ralph Nader spoke at the rally.

Shortly after 1 p.m., the crowd at the Washington Monument started marching toward the King Memorial. A group of women shouted, “We! Are! The 99 per cent!” Others chanted, “Who’s got the power? We’ve got the power! People power!”

A gray-haired man in a blue-striped button-down shirt held a sign aloft: “I am not an angry young hippie! I am a middle-aged angry businessman!” People held signs that read “Save the middle class.”

And as marchers rounded the turn onto the monument grounds, where the pale stones loomed against bright-blue sky, people sang softly, “We shall overcome . . .

Staff writer Tim Craig contributed to this report.