The Supreme Court will hear three days of arguments starting Monday on whether President Obama’s Affordable Care Act is constitutional. Twenty-six states have filed challenges to the health-care reform law. The main issue, on which the lower courts have split, is whether Congress had the power to pass this law under the Constitution’s commerce clause. The answers to that and other questions are clouded by misperceptions about the law itself. Let’s debunk them.

1. The “individual mandate” forces everyone to buy health insurance.

The law states that, beginning in 2014, individuals must ensure that they and their dependents are covered by health insurance. Taxpayers who do not meet this requirement will have to pay a penalty that the law calls a “shared responsibility payment.” It begins at $95 for the first year and never exceeds 2 1/2percent of anyone’s annual taxable income.

A large majority of Americans, of course, have health insurance through their employers, Medicare or Medicaid and are already in compliance with this requirement. Given the relatively modest payment required of those who choose not to maintain insurance, no one is being forced to buy a product they don’t want.

The challengers argue that the mandate is a binding requirement that makes anyone who goes without insurance a lawbreaker. The government has determined, however, that those who pay the penalty, like those who are exempt from the penalty, are not lawbreakers. As a practical matter, the so-called mandate is just a relatively modest financial incentive to have health insurance.

2. Only the individual mandate is at stake in the Supreme Court case.

The mandate is not a stand-alone provision that can be invalidated without affecting the rest of the law. In fact, it is merely an ancillary measure that makes two more-fundamental provisions of the law workable: “guaranteed issue” and “community rating.”

A significant problem with our nation’s health-care system has been that insurance companies can reject applicants who have had health problems, including minor ones. The guaranteed issue provision prevents companies from turning down applicants because of their medical conditions or history. The community rating measure bars insurers from charging higher premiums to those who have had illnesses or accidents.

Experience in the states has shown that if people can’t be turned down for health insurance, there must be an incentive for them to sign up for it before they have an accident or illness. The individual mandate was enacted to ensure that the central, nondiscrimination provisions can work as they were intended — to provide everyone access to affordable health care, regardless of their medical history or current conditions. If the court were to strike down the mandate, the law’s popular provisions on preexisting conditions would fall as well.

3. If the court upholds the health-care law, it means Congress has the power to require Americans to purchase any product.

The health-care case is a test of Congress’ power under the Constitution to regulate commerce among the states. One way to defend the law is simply to say that a requirement to purchase insurance or any other product sold in interstate commerce is obviously a regulation of that commerce. President Ronald Reagan’s solicitor general, Charles Fried, and conservative judge Laurence Silberman have adopted this view.

The Obama administration is not relying upon such a sweeping argument, however, and its more limited claim would not justify any law that required Americans to buy products such as cars or broccoli.

The mandate does not force people into commerce who would otherwise remain outside it. Instead, it regulates the consumption of health care, an activity in which virtually everyone will engage. Right now, people who go without insurance often shift the costs of their health care to other patients and taxpayers. That situation is different from what happens with any other type of purchase.

Would the government’s defense of the mandate also support a law requiring Americans to buy broccoli or a car? The answer is a simple and emphatic no.

4. The law is socialist.

Actually, the opposite is true. The principal reason the Affordable Care Act has been called unprecedented is that it declines to follow the New Deal approach of having a monolithic government agency be the single provider of a good or service. Instead, the law adopts a new approach, one conservatives have long supported, of using providers in the private market to deal with social and economic problems.

In defending his “Massachusetts mandate” as a conservative model for national health-care legislation, former governor Mitt Romney editorialized in 2009 that by imposing tax penalties on people who choose to remain uninsured, an individual mandate “encourages ‘free riders’ to take responsibilities for themselves rather than pass their medical costs on to others.” And, as Romney noted, conservatives have never been inclined to favor freeloaders.

5. The law is an extraordinary intrusion into liberty.

Liberty is always said to be fatally eroded, it seems, when great advances in social legislation take place. The lawyers who urged the Supreme Court to strike down the Social Security Act of 1935 argued that if Congress could provide a retirement system for everyone 65 and older, it would have the power to set the retirement age at 30 and force the very young to support everyone else.

It was said that if Congress had the authority to create a minimum wage of $5 an hour, it would also be a regulation of commerce to set the minimum at $5,000 an hour. In 1964, critics argued that if Congress could tell restaurant owners not to discriminate on the basis of race, it could tell them what color tablecloths to use. None of these things happened.

Nothing in the health-care law tells doctors what they must say to patients or how those patients are to be treated. It only requires people to either have insurance coverage or pay a modest tax penalty.

Nearly 75 years ago, a Supreme Court dominated by appointees of conservative presidents rejected the challenge to the constitutionality of the Social Security Act. The words of Justice Benjamin Cardozo’s 1937 opinion are relevant today:

“Whether wisdom or unwisdom resides in 1/8the statute in question 3/8 it is not for us to say. The answer to such inquiries must come from Congress, not the courts.”

Walter Dellinger served as head of the Justice Department’s Office of Legal Counsel and acting solicitor general from 1993 to 1997. He filed a brief on behalf of the Senate and House Democratic leadership defending the health care law in the Supreme Court.