WASHINGTON — On a White House lawn crowded with people in wheelchairs, President Bush signed landmark legislation Thursday banning discrimination against the nation’s 43 million disabled.

“Every man, woman and child with a disability can now pass through once-closed doors into a bright new era of equality, independence and freedom,” Bush said as he signed the Americans with Disabilities Act.

He called it “another Independence Day, one that is long overdue.”

The crowd of more than 3,000 that spilled across the South Lawn was the largest ever at a White House bill-signing ceremony, said deputy press secretary Alixe Glen.

Many of those attending were disabled, and they applauded loudly as Bush said the law will ban discrimination in the workplace, ensure access to restaurants, hotels and shopping centers, expand access to public buses and rail systems, and require telephone companies to provide special services for the deaf.

The law bans discrimination against people with disabilities, including AIDS, and defines a disabled person as anyone with a mental or physical impairment limiting “some major life function.”

Bush invoked the opening words of the Declaration of Independence, saying, “we are keeping faith with the spirit of our courageous forefathers who wrote … `that all men are created equal.”‘

“Tragically, for too many Americans, the blessings of liberty have been limited or even denied,” Bush said.

The president likened the Americans with Disabilities Act to the dismantling of the Berlin Wall. The law “takes a sledgehammer to another wall,” he said.

“We will not accept, we will not excuse, we will not tolerate discrimination in America,” Bush said.

When he sat down at a table to sign the bill with a flourish of ceremonial pens, many in the crowd rose for a better view, only to sit quickly back down as those in wheelchairs called out, “Down in front!”

Bush offered the fourth and last pen to the Rev. Harold Wilke, 75, an armless United Church of Christ minister from Claremont, Calif., who had delivered an invocation that spoke of “the breaking of the chains which have held back millions of Americans with disabilities.”

Wilke, who teaches at Union Seminary in New York City, suggested the pen go instead to Ginny Thornburgh, wife of the attorney general and a longtime activist for the disabled.

“The president said, `All right, I’ll give it to Ginny, but I’ll give you mine,”‘ Wilke said later.

As Bush reached into his pocket, Wilke deftly slipped his foot out of his loafer, took the pen with his toes and slipped it back into his shoe. A moment later, seated beside Barbara Bush, he put the pen into his pocket.

Those watching the ceremony were enthusiastic.

“It’s just fantastic. It’s a tremendously exhilarating feeling,” said Gordon Anthony, 35, an activist from Los Angeles in a wheelchair from a spinal cord injury.

Anthony is a successful marketing consultant, but he said the law “may open doors for what I do in my future career. There may be better opportunities.”

“Employers are going to start reaching out to the disabled,” he said.

Maggie Behle, 10, of Salt Lake City, darted nimbly through the crowd on a single crutch. She was born with one leg, but is a downhill ski racer.

Her mother, Sue Behle, boasted that Maggie has encountered few obstacles she cannot overcome, but the Behles have a second daughter, Kate, 15, who is autistic and retarded.

Mrs. Behle, who works with a state agency for the handicapped, said she hopes the Americans with Disabilities Act “will mean that Kate can have a job, that she can be employed.”

Karen Friedman of the Human Rights Campaign Fund, which lobbies for gay causes, called it a “very historic day because it will stop discrimination against people with AIDS and HIV infection.”

The disabilities bill includes sanctions for those who discriminate in hiring. It allows victims of employment discrimination to seek back pay, reinstatement and attorneys’ fees. However, the law exempts businesses with fewer than 15 employees from the hiring provisions.