WASHINGTON -- The U.S. Supreme Court shifted Wednesday to the question of whether President Barack Obama's health care overhaul can survive if the court were to strike down the core provision that requires all Americans to have health insurance.
The prospect of it being struck down seemed to increase Tuesday as justices challenged the provision, casting doubt on a law that's considered Obama's signature achievement and would affect virtually every American. The court's decision could come in June, in the midst of the campaign before November's presidential election.
Wednesday is the last of three days of arguments over the health law, which has the goal of extending health insurance to 30 million Americans who have no coverage but has come under spirited challenge by 26 states and a business group. Opponents contend the law unconstitutionally extends the power of the federal government.
Before the reforms were signed into law two years ago, the United States was the only developed country without a national health care program.
The justices will spend part of the day considering the states' challenge to the expansion of the federal-state Medicaid program for low-income and disabled Americans, an important feature of the plan.
The court's decision, regardless of how it turns out, likely will intensify the ideological differences splitting the country.
Wednesday's session will hear opponents of the law arguing that the requirement to buy insurance is central to the whole undertaking and should take the rest of the law down with it.
The Obama administration argues that the only other provisions the court should kill if the insurance mandate is stricken are ones that require insurers to cover people regardless of existing medical problems and limit how much they can charge in premiums based on a person's age or health.
The federal appeals court in Atlanta that struck down the insurance requirement said the rest of the law can remain in place, a position that will be argued by H. Bartow Farr III, a private lawyer appointed by the justices.
In a day of contentious questioning Tuesday, conservative justices on the nine-member court pointedly challenged the core provision of the historic health care law, casting doubt on the requirement that all Americans must buy insurance coverage or face a penalty.
Arguments focused on whether the so-called insurance mandate "is a step beyond what our cases allow," in the words of Justice Anthony Kennedy, who often is the swing vote on the court.
The high court justices are appointed for life terms by the president in office when vacancies occur. It currently is made up of four Democratic-appointed, reliably liberal judges and four Republican-appointed conservatives. Kennedy, while chosen by conservative Republican President Ronald Reagan, can vote with either camp depending on the issue.
While he sharply challenged the mandate, Kennedy also conceded that the absence of the requirement affects "the rates of insurance and the costs of providing medical care in a way that is not true in other industries."
Chief Justice John Roberts, appointed by President George W. Bush and typically a reliable conservative, also challenged the arguments of the lawyer representing the law's opponents.
"Everybody is in this market," Roberts said. "So that makes it very different than the market for cars or the other hypotheticals that you came up with, and all they're regulating is how you pay for it."
The health care overhaul, which squeaked through Congress when Democrats still controlled both houses, is constructed to expand the number of people who have insurance, including young and healthy people who may have fewer needs for the system.
That is designed to offset losses to insurance companies, which would now be prevented from denying coverage to people who already have health problems _ so-called pre-existing conditions.