By SEAN COLLINS WALSH
http://thecaucus.blogs.nytimes.com/author/sean-collins-walsh/

Hundreds of members of the nation’s largest nurses’ union demonstrated outside the U.S. Chamber of Commerce and on Capitol Hill on Tuesday.

The union, National Nurses United, held the event to promote its “Main Street Contract for the American People,” which aims, in part, to increase tax revenue from corporations to prevent cuts in entitlement programs like Medicare and Medicaid.

The protesters started in Lafayette Square and marched to the chamber’s headquarters. Two demonstrators in tuxedoes — one labeled “Goldman” and the other “Sachs” — collected “invoices” of demands like “pension contribution increases” and “Mortgage payments” from nurses on the steps of the building.

After the event, a spokeswoman from the chamber said the country’s corporate tax burden was too high as it is.

“The chamber welcomes all voices to the debate, but the debate has to remain focused on creating American jobs and keeping our economy growing,” the chamber’s director of communications, Blair Latoff, wrote in an e-mail. “Right now U.S. businesses are saddled with one of the highest corporate tax rates in the world, which is undercutting our global competitiveness.”

Ms. Latoff, who did not see the protest but learned of it afterward, also noted that President Obama supported lowering the corporate tax burden. In his most recent State of Union address, Mr. Obama said he wanted Congress to close loopholes in the tax code and “use the savings to lower the corporate tax rate for the first time in 25 years.”

After the chamber demonstration, protesters boarded buses to Upper Senate Park for a rally, which included a speech by Senator Bernie Sanders, independent of Vermont.

“From birth to death, the people who are at our sides when we get sick are our nurses,” he said.

Mr. Sanders recently introduced a bill to create a single-payer health care system, which would require state governments to provide universal coverage. The measure is not expected to move forward.

“Health care must be a right for all people,” Mr. Sanders said at the rally. “We are at that moment where we got to push. We got to shove.”

Senator Barbara Boxer Democrat of California, also spoke.

“The Republicans once had a ‘Contract With America,’” Mrs. Boxer said, referring to the agenda the Republican Party used to capture the House in 1994. “I’m ready for a good contract, and this is it.”

After the rally, representatives from the nurses’ union met with members of Congress to lobby for support.

Although much of the union’s political support comes from liberals, National Nurses United has a nonpartisan mission, the executive director of the group, Rose Ann DeMoro, said in an interview. Mr. Sanders’ comments on a single-payer system were not intended to be the theme of the day, she said.

Ms. DeMoro, in a letter in The New York Times last month, criticized both sides of the debate over entitlement spending. In it, she called the plan of Representative Paul D. Ryan, Republican of Wisconsin and chairman of the House Budget Committee, to turn Medicaid into a block grant program a “thinly veiled scheme to destroy” the program and attacked the Democrat-backed health care overhaul last year because it “expands the role of private insurers.”

“The politicians spend all our time lowering our expectations about what is possible,” Ms. DeMoro said on Tuesday.

Calls for increased governmental involvement in the health care system are unlikely to gain traction any time soon. After the midterm elections, in which Republicans took control of the House, the House voted to repeal the law. The measure was defeated in the Democrat-controlled Senate.

Many nurses at the rally said they were concerned that staffing reductions in hospitals and doctors’ offices due to budget cuts could be dangerous to patients.

“People are suffering, because there are not enough nurses at the bedside,” said Pamela Young, 54, who traveled from Oviedo, Fla., for the event.

With more than 160,000 members, National Nurses United formed in 2009 with the consolidation of three unions: United American Nurses, Massachusetts Nurses Association, and California Nurses Association/National Nurses Organizing Committee.