The study was conducted by a group of political science professors and published this week by American Politics Research. It found that, had it not been for the health care law, House Democrats likely would have held at least 25 seats and maintained their majority.
House Democrats lost 63 seats in 2010, giving Republicans their largest Congressional majority since World War II.
It was an outcome few predicted. The study notes that the median academic forecast of net Democratic losses before the election was just 44 seats.
"It was never going to be a good year for the majority party given the number of marginal seats they had to defend, the weak economy, and the president’s middling approval ratings, but few observers thought they would lose 63 House seats," the authors write. "Our analysis suggests one possible reason for these losses: health care reform."
More than any other piece of legislation examined in the group’s analysis, which also looked at the cap-and-trade bill and the stimulus package, or any other factors such as party loyalty or ideological perception, Democratic support for health care reform was most strongly correlated with the criteria deemed necessary to produce a "public backlash."
The primary reason for this, the authors suggest, is that voting yes on the Affordable Care Act caused Democratic lawmakers to be viewed by their constituents as more liberal and "out of step," costing them votes. Specifically, the study found the voters were five percentage points less likely to support incumbents who voted for the health care bill than for ones who opposed it.
"Support for controversial legislation causes voters to see their representatives as more ideologically distant," the authors write. "Democratic incumbents who supported health care reform were perceived by many of their constituents as more liberal than the individual constituents themselves."
"Health care reform was a bold move by Democrats, and it prompted a strong response," they conclude.
The findings arrive at a time when public opposition to the health care law is on the rise. Last month, a Quinnipiac poll found that voters support Republican efforts to repeal the law by a 52 percent to 39 percent margin.
On Thursday, the Associated Press published a poll that found opposition to the law at roughly the same level as when it was passed in March 2010. According to the poll, 47 percent of Americans currently oppose the law, compared with just 35 percent who support it. Two years ago, 50 percent opposed the law and 39 percent supported it.
Americans are particularly opposed—by a nearly 3-to-2 margin—to the law’s requirement that all individuals must purchase health insurance or pay a government fine.
The law has been the source of considerable controversy lately as a number of President Obama’s core promises with respect to the law have unraveled.
For instance, a 2011 study by the McKinsey Group estimated that between 30 percent and 50 percent of Americans could be forced off of their current health insurance plans under the new law.
Obama has repeatedly claimed that individuals who are satisfied with their current health insurance plans will be able to keep them.
"First of all, if you’ve got health insurance, you like your doctors, you like your plan, you can keep your doctor, you can keep your plan," he said in July 2009. "Nobody is talking about taking that away from you."
Additionally, the law’s supporters claim it will reduce the federal deficit by $143 billion over the next decade, a figure derived from Congressional Budget Office estimates. More than half of that number was wiped out when the administration acknowledged that a particular provision of the law—the Community Living Assistance and Support Services (CLASS) Act—was financially unsustainable and decided to cease trying to implement it. When the program was halted, the CLASS Act had been projected to account for about $86 billion in deficit reduction.