WASHINGTON, D.C. -- With Monday's deadline for enrolling in an insurance plan past, no other factor -- including race, income, personal ideology, gender, or education -- is as relevant to Americans' opinions on the Affordable Care Act as their party affiliation. This remains the foremost predictor of whether an individual will disapprove of the ACA.

These results stem from an aggregated set of surveys in which Gallup measured approval of the ACA. The data span August 2013 to March 2014 and include interviews with 13,797 U.S. adults. Overall support for the ACA remained low throughout this period, even as the various components of the law rolled out.

Of the majority of Americans who disapprove, nearly seven in 10 are self-identified Republicans or individuals who lean toward the GOP. Democrats and Democratic leaners make up less than a fifth of those who disapprove of the law. The remaining 14%, based on their survey responses, cannot be classified as Republicans or Democrats.

While party identification highly predicts support, other factors also play a role, including race and ideology, though not to the same degree. Characteristics such as income and employment status, which one might think are important when it comes to support for legislation aiming to help the uninsured get insurance, are not significant predictors.

The larger data set did not contain information about individuals' reported health insurance status or descriptions of their health, but a subset of the data consisting of 3,572 interviews conducted in 2014 did. When health insurance status or ratings of one's own health were included, neither proved significant. Again, self-identified party affiliation was by far the most influential factor.

Party ID Trumps All When Assessing Future Impact of Law

Likewise, party affiliation is the biggest determinant of one's views toward the ACA when Americans are asked if the healthcare law will make their family's healthcare situation worse. Republicans are about 16 times more likely than Democrats to say the healthcare law will negatively affect their family's healthcare in the long run, with independents nearly five times more likely than Democrats to do this.

When projecting the long-term effect of the healthcare law on the nation, Republicans are about 22 times more likely than Democrats to say the law will make things worse. Independents are four times as likely as Democrats to say the law will make things worse.

Implications

The healthcare law is highly political. From its initial party-line passage, to its continued lightning-rod status for Republican politicians and candidates, to its informal label of "Obamacare" forever linking the law to the Democratic president, the ACA has remained a centerpiece of the nation's political debate, even as it becomes more firmly established in law. But the extraordinary importance of party identification in predicting a person's support for the legislation raises the question of whether the ACA can ever escape its polarizing branding and be accepted by policymakers -- present and future -- as settled law, rather than an ongoing political battle.

The healthcare law will undoubtedly be debated over the course of this year's midterm elections that could leave the Republican Party in control of both houses of Congress. But unless the GOP is able to obtain a difficult two-thirds majority in the House and the Senate, efforts to repeal or drastically alter the law will likely be unsuccessful at least through the 2016 presidential election, ensuring it remains a political football for the next few years.