Now that the Supreme Court has upheld his historic health care law, President Barack Obama ought to seize the term “Obamacare” and make it his own.

Conservatives have sought to depict the Affordable Care Act as a gross intrusion by the federal government, tagging it with a label they thought would cling to the president who was the law’s champion. Obama ought to wave that label proudly. Obamacare is a historic achievement.

It is remarkable that it was Chief Justice John Roberts who came to the rescue of the law, though his reasoning drew criticism from Justice Ruth Bader Ginsburg. On the question of the individual mandate, which penalizes people who choose not to buy health insurance, Roberts said, in essence, that the mandate was unconstitutional but the penalty was permitted.

Congress based the individual mandate on the Commerce Clause of the Constitution, which grants Congress the power to regulate interstate commerce. Roberts said that commerce first must exist before it is regulated and that Congress is not empowered to compel commerce into existence — by ordering someone to buy insurance. Thus, Roberts accepted the broccoli argument, put forward by those who said if Congress could order us to buy insurance, it could also order us to buy broccoli. In both cases, Roberts said, Congress does not have that power.

But Congress does have the power to impose a tax on those who do not buy health insurance, according to Roberts, and he found that the penalty enacted by Congress to be levied against those who do not buy insurance could be construed as a tax.

Ginsburg rejected Roberts’ view of the Commerce Clause. “The chief justice’s crabbed reading of the Commerce Clause harks back to the era in which the Court routinely thwarted Congress’ efforts to regulate the national economy in the interest of those who labor to sustain it,” she wrote in an opinion joined by Justices Elena Kagan, Stephen Breyer and Sonia Sotomayor.

Roberts’ majority opinion goes to some lengths to distinguish between activity and inactivity in commerce, arguing that people are not engaged in interstate commerce if they are not at the moment engaged in buying insurance. The purchase of a car, or of broccoli, he wrote, may affect interstate commerce, but that potential effect does not allow Congress the power to compel someone into the marketplace to buy a car or broccoli.

That distinction is absurd, Ginsburg argued. We are all in the health care market because we will all at some point need health care, and our decision not to buy insurance has wide ramifications throughout the system.

Nevertheless, Roberts’ willingness to approve the Affordable Care Act on the basis of Congress’ taxing power represents a major victory for Obama and the Democrats. Now Obama can trumpet from the platform the many benefits of the law.

Sen. Patrick Leahy’s office issued a list of the benefits already gained in Vermont. Already Vermont has received nearly $40 million to help pursue health reform. This money includes $18 million to establish a health care exchange in Vermont; a $1 million planning grant; $5.3 million to encourage preventive care; $10.9 million to help create community health centers in underserved areas.

Sen. Randy Brock, the Republican candidate for governor, issued a statement Thursday saying that the Supreme Court ruling only postpones the “day of reckoning” when what he calls “Titaniccare” is bound to sink. Yet millions of Americans have already gained health care coverage as a result of Obamacare, and insurance company profiteering has been severely circumscribed.

Now is the time for Obama and the Democrats to come up out of their defensive crouch on health care and to embrace the good that they have done. People will not be mandated to buy health insurance, but those who lack it may well avail themselves of new insurance options as they can. That they must pay an additional tax if they choose not to, thanks to Chief Justice Roberts, gives them an extra incentive.