Washington (CNN) -- Conservative activists tried to put the brakes on health care reform Tuesday, holding rallies on Capitol Hill intended to sway wavering Democrats days before a final expected House of Representatives vote on a sweeping $875 billion measure.
The plan, which would constitute the biggest expansion of federal health care guarantees since the enactment of Medicare and Medicaid more than 40 years ago, passed the Senate in December.
If it clears the House, it will go to President Obama's desk to be signed into law. Although Democrats still plan to make revisions to the bill, final passage of the landmark measure would be a huge victory for the president.
It would also mark a major legislative defeat for Republicans and their allies in the conservative movement.
"If [the] bill can't pass the House, scrap the bill, start over," Rep. Mike Pence, R-Indiana, told demonstrators from a range of conservative organizations, including the Tea Party Express, Americans for Prosperity and FreedomWorks.
Christina Latchford of Florida said she opposes the individual coverage mandates in the bill, as well as the methods being used by Democrats to push it through Congress.
"The way they're trying to put it through is unconstitutional," she said. "One house is not approving it, and the other is trying to pass it. [That's] my understanding."
Latchford was referring to a strategy being considered by House Speaker Nancy Pelosi that would allow House Democrats to avoid a direct vote on the Senate bill. The speaker may call for a vote on a rule that would simply "deem" the Senate bill passed. The House then would proceed to a separate vote on changes that would make the legislation more acceptable to House Democrats.
"That goes totally against the Constitution," Latchford said. Both chambers must pass individual bills before they can be signed into law, she said.
Luis Padilla, a Virginian who is originally from Latin America, said he turned out for the rally because for the "10 years that I've been in this country, I've been making my own decisions -- the doctor, the dentist ... and I want to keep it that way."
Padilla said he believes that the bill would take his medical choices away while providing a handout he doesn't want.
"I don't expect the government to pay for me," he said. "If I come to this country expecting the government to take care of my family, to take away my responsibility, it takes away the incentive for me to prosper, the incentive for me to get a better job.
"I want to do it myself," he said.
James Bond said he temporarily closed his cleaning business in Wilmington, North Carolina, to attend the rally. He said he wants to "protest against the economic terrorism going on in Washington with the passage of this bill."
"I'm very concerned with the price tag associated with it," he said. "I would really love to see things worked out where we do have insurance reform but at a reasonable price."
Bond's 7-year-old daughter, Taylor, was riding on her father's shoulders dressed as the Statue of Liberty. She cheerfully shouted the word "liberty" as people gathered for the demonstration at a park across from the U.S. Capitol.
Jim Fernander of Douglas Hill, Georgia, says he doesn't like the bill. "I don't want the same people that run the post office running my health care."
Informal estimates put the number of protesters between 500 and 1,000.
CNN's Alan Silverleib contributed to this story.