For years, US president Barack Obama has faced the sneers of political adversaries who called his health care law Obamacare and assailed his effort to build a legacy that has been the aspiration of every Democratic president since Harry S Truman.

But on Thursday, Obama walked into the Rose Garden to accept vindication as the Supreme Court, for a second time, affirmed the legality of a part of the Affordable Care Act.

The president said the law “is working exactly as it’s supposed to” and called for an end to the vitriolic politics that have threatened it.

"The point is, this is not an abstract thing anymore," Obama told reporters, with vice-president Joe Biden smiling broadly beside him. "This is not a set of political talking points. For all the misinformation campaigns, all the doomsday predictions, all the talk of death panels and job destruction, for all the repeal attempts – this law is now helping tens of millions of Americans."

Obama’s plea to stop “refighting battles that have been settled again and again and again” met this week with immediate resistance.

The Republican Speaker of the House, John Boehner, promised to "do everything we can" to undermine the law. Jeb Bush, a Republican candidate for president, vowed "to repeal and replace this flawed law" if he succeeds Obama in the Oval Office.

Boehner said he would continue to move forward with a lawsuit against the president, arguing that Obama overstepped his legal authority in carrying out the health care act. Other Republicans mused about using parliamentary manoeuvres to chip away at the law.

Personal affirmation

For Obama, the ruling was a personal affirmation of the wisdom of engaging in a costly political fight that began almost as soon as he took office.

The court's ruling, Obama said on Thursday, cements the Affordable Care Act in US history as the logical extension of Social Security and Medicare.

“This generation of Americans chose to finish the job,” Obama said, reading from one of two sets of remarks – one written as if the Supreme Court upheld the subsidies and another as if the court did not.

The ruling came as Obama is heading toward another major legislative accomplishment – the passage of powerful new authority that will allow him to finish negotiations on a historic trade agreement with Pacific Rim nations. He pushed that Bill over the objections of many in his own party.

Still, the Supreme Court decision is the bigger victory at home for Obama, whose domestic policy legacy has always depended on the Affordable Care Act’s becoming a permanent part of the US health care system by the time he leaves office in 2017.

Legal challenges

Unable to halt the implementation of the law in Congress, Republican lawmakers, governors and others turned to the courts, betting that successful legal challenges would prevent Obama from establishing the Affordable Care Act as an accepted companion to Medicare and Medicaid.

Instead, the two main legal challenges to the law have largely failed.

In 2012, the Supreme Court slowed the law’s expansion of Medicaid, but let stand the individual mandate that requires people to purchase health insurance. And, in Thursday’s ruling, the court said the federal government could provide subsidies to people purchasing coverage through a federal insurance marketplace.

The court decision ended months of speculation and worries among administration officials, health experts, lawmakers from both parties and insurance company executives about the potential for chaos in the insurance markets if the justices had gone the other way.

Higher premiums

Officials had predicted a cascading series of events if the subsidies were invalidated: premiums for millions of people would have doubled or tripled. That would have forced many to drop insurance altogether, causing insurers to drastically raise rates or stop selling plans.

In the worst-case scenario, officials predicted a collapse of the individual health insurance market in many states.

The court’s decision means that Obama’s administration will continue to enrol people in private, but subsidised, health insurance. About 10 million people have already bought insurance from state or federal marketplaces. Officials are hoping to enroll millions more by the time Obama’s term ends.

Despite writing the decision, chief justice John Roberts also made a point of chiding the lawmakers who drafted the law and, by association, the president who pushed them to do it.

Early in his tenure, Obama had said he hoped for bipartisan cooperation on fashioning a new approach to health care that would lower costs while providing coverage to the tens of millions of uninsured.

When Republicans balked, the Democrats – who then held majorities in the House and Senate – went ahead and passed it.

Roberts said it would be “charitable” to accuse the authors of “imprecision”. He noted that the bill was written in secret and passed with special parliamentary procedures that limited opportunities for input or revision.

The judge said the resulting law “does not reflect the kind of care and deliberation that one might expect of such significant legislation”.

– (New York Times service)