When Democrats passed the Affordable Care Act in 2010 without a single Republican vote, they were criticized for being too partisan. In the end, however, the bill included many Republican ideas.

The keystone principle of the act — a mandate that all Americans buy health insurance — is rooted in conservative thinking. Additionally, the Democrat-controlled House and Senate committees adopted nearly 190 Republican amendments while writing the legislation, according to data compiled by The New York Times.

Amendments from the minority party that were adopted

0 188 Republican amendments in the Affordable Care Act Democratic amendments in the Republican plan 0 188 Democratic amendments in the Republican plan Republican amendments in the Affordable Care Act

In contrast, Democrats have complained that they had no input in creating any of the Republican health care plans proposed this year. Democrats, who have submitted numerous proposals, said they would further participate if Republicans dropped their insistence on repealing the Affordable Care Act.

“The door to bipartisanship is open right now, not with repeal but with an effort to improve the existing system,” said Senator Chuck Schumer of New York, the minority leader.

“We’re ready to sit down, right now, if Republicans abandon cuts to Medicaid, abandon huge tax breaks for the wealthy, and agree to go through the regular order — through the committees, with hearings, onto the floor, with time for amendments,” he said.

House Democrats proposed 29 amendments to the House version of the Republican bill, but none of them passed.

Some were symbolic protests that were not particularly meaningful, like a proposal to change the title of the bill to the “Republican Pay More for Less Care Act.” But others were more substantive, like measures to protect subsidies to help people pay for deductibles.

Republicans have argued that many of the amendments that they proposed that were adopted in 2009 were procedural instead of substantive. For example, Senator Lisa Murkowski, Republican of Alaska, at the time said that the amendments she introduced successfully “were all technical.”

Many substantive amendments, however, were adopted, including provisions requiring members of Congress to purchase insurance through the public health exchanges and allowing small businesses to band together to provide coverage.

The Times compiled the list of amendments from 2009 to 2010 as well as from this year, from publicly available databases and records provided by the five House and Senate committees directly involved in drafting health care legislation.

A comparison of amendments to the Affordable Care Act and the Republican plan

Republican plan Majority party

amendment Minority party

amendment Bipartisan amendment Amendments adopted 8 0 0 Failed 0 29 0 Affordable Care Act Amendments adopted 169 188 17 Failed 13 201 3 Note: Amendments that were withdrawn or ruled nongermane are not included. Numbers for the Republican plan include only amendments proposed in the House; the Senate’s draft legislation has not yet made it to the floor.

Senate Republican leaders have proposed four versions of their plan, but at least twice, the bills have failed to reach the floor because several Republican senators announced their opposition. They are trying to pass a bill without Democratic support, and their slim two-vote majority leaves little room for Republican dissent.

“It’s really hard to thread that needle when you have different groups that oppose the bill for such different reasons within the same party,” said Allison K. Hoffman, a health care policy expert and law professor at the University of Pennsylvania.

Soon after the Senate bill collapsed this week, Mr. Schumer urged Republican lawmakers to start fresh and pursue a bipartisan effort — an idea that Mr. McConnell had floated a few weeks ago, when he realized his bill was in trouble.

“The A.C.A. is a bill that is very bipartisan in nature,” Ms. Hoffman said. Critical ideas for the Affordable Care Act were borne of more conservative thinking, she said.

The federal mandate to buy insurance is similar to a mandate that Mitt Romney, the 2012 Republican presidential candidate, had enacted as Massachusetts governor. The concept that people should be required to buy health coverage originated with conservative economists two decades ago and was initially embraced by conservative research groups, like the Heritage Foundation.