Thousands of people gathered outside Faneuil Hall on Sunday in protest of an effort by the president-elect and congressional Republicans to revoke President Obama’s signature health care law.
“Donald Trump hasn’t even been sworn in,” Senator Elizabeth Warren said to a chorus of boos from the crowd, “but he and his Republican allies are already trying to ram through repeal of the Affordable Care Act.”
Warren and other members of the Massachusetts congressional delegation joined Mayor Martin J. Walsh at the event, which drew a crowd estimated by city officials at more than 6,000.
Many of those who attended carried signs with messages such as “Don’t make America sick again,” “Single payer now,” and “Care not chaos.”
“We are here today — thousands strong in Boston, and at more rallies all across this country — because we will make our voices heard,” Warren said. “If Republicans try to rip health care out of the hands of millions of Americans, we will fight them every step of the way.”
Trump has promised to repeal and replace the health care law, and the Republican-controlled Senate on Thursday passed a measure taking the first steps to dismantle it.
On Sunday, the Boston rally was one of many nationwide attended by congressional Democrats, other elected officials, and labor organizers.
Police estimated about 600 people participated in a demonstration in Portland, Maine. In Providence, all four of Rhode Island’s US senators and representatives spoke to the crowd of hundreds, as did Governor Gina Raimondo.
In Boston, several speakers noted the significance of the rally’s location: Faneuil Hall was an important site in fomenting the American Revolution, advocating the abolition of slavery, and promoting the right of women to vote — as well as host to the elaborate 2006 ceremony where then-governor Mitt Romney signed Massachusetts’ universal health care law, a template for the Affordable Care Act.
“I remember the moment well,” said Walsh, who was then a state representative, “because it was one of my proudest moments, and one of my proudest votes I ever cast as a member of the Legislature.”
Warren and Walsh were joined on stage by most of the state’s congressional delegation, along with a health care worker, the chief executive of Boston Medical Center, and other private citizens who shared deeply personal stories of health crises.
Janis McGrory, a Harwich resident, spoke of her 23-year-old daughter, Liz, who died of an accidental overdose in 2011, and the health care law’s provisions for addiction treatment.
“Her story is much like thousands of others’ suffering from this disease that need treatment, like any other disease,” McGrory said. “The Affordable Care Act provides access to such treatment. It provides hope.”
Only two US representatives from Massachusetts did not attend the rally: Michael E. Capuano and Stephen F. Lynch.
Capuano, a Somerville Democrat, was on a long-planned family vacation, a spokeswoman said, but he issued a statement affirming his commitment to preserving the law.
“I am a strong supporter of the Affordable Care Act and will work hard in Washington to preserve it,” Capuano said.
Lynch’s office could not immediately be reached for comment.
Many in the crowd at Faneuil Hall had their own stories of concern about medical conditions and insurance coverage.
Abby Kessler, of West Newton, is a self-employed acupuncturist. In the past, she said, she had been unable to afford the “astronomical insurance costs for a business of one.” She is now covered under the health care law, she said, which gives her peace of mind.
“I’m in my fifties, so I was playing Russian roulette by not having insurance,” Kessler said.
Sunny Patel, a resident physician at Cambridge Health Alliance, attended the rally in his white lab coat, holding a sign that read, “Patients before politics.”
“As doctors, we took an oath, the Hippocratic oath, that says we do no harm,” Patel said. “By choosing politics over patients, we are harming the health of our country.” He said about 30 doctors came to the rally to stand up for their patients who are helped by the law.
The rally was not without dissent. One man carried a sign that read, “You don’t speak for all immigrants,’’ on one side and, “Lost my doctor, lost my plan,” on the other. He declined to speak to a reporter, but chanted, “No free health care. Earned health care.”
Most in the crowd, though, voiced sentiments like those of Javier Matamoros, 33, who said he’s fortunate enough to not need most of the provisions in the law but came out to support those who do.
“There are people who would be sick or dead [without the law],” he said. “It’s immoral to take away a program that’s helping people, no matter its faults.”
Globe correspondent Martha Schick and material from the Associated Press contributed to this report. Jeremy C. Fox can be reached at email@example.com. Follow him on Twitter @jeremycfox.