Anyone who doubts the political nature of the high court need only look to the 5-4 decision in 2000's Bush vs. Gore, which stopped the presidential recount in Florida.
At the time, the five conservatives were considered the protectors of federalism, championing the rights of the states against the power of the federal government. The four liberals were more likely to see the federal government and the Constitution as the protector of individual rights.
Nevertheless, the five conservatives brushed aside a ruling by the Florida Supreme Court that interpreted state law as backing the recount, saying the recount method violated the equal protection guarantee of the Constitution.
In vain, the liberals filed four dissents defending the right of Florida to run its own elections.
The cynical view: Whenever an extremely important issue is political to the bone, individual justices will follow their political preferences when trying to forge a ruling, sometimes going through constitutional gymnastics to reach their conclusions.
What's more, the justices seem not to care about how political they are perceived.
Some Republicans are pressing for Justice Elena Kagan to "recuse" herself, or step down, from the case because she was the Obama administration's top courtroom lawyer when the Patient Protection and Affordable Care Act was rammed through Congress over bitter Republican opposition.
Across the aisle, some Democrats are demanding Justice Clarence Thomas withdraw from the case because of his wife's links to organizations dedicated to killing the federal law.
Incredibly, on the same day the Supreme Court decided behind closed doors to accept the challenge, Thomas and Justice Antonin Scalia "were feted at a dinner sponsored by the law firm that will argue the case before the high court," the Los Angeles Times reported.
The two justices were the featured guests at the Federalist Society dinner in Washington.
None of the justices has indicated a willingness to step down before the challenge is heard for 5 1/2 hours in March.
So the odds at the Supreme Court are still weighted in favor of the challengers, if only slightly, and the high court probably will rule against the law.
Or maybe not. It might be useful to ask ourselves, as Scrooge asked the Spirit of Christmas Yet to Come, "Are these the shadows of the things that will be or are they the shadows of the things that may be, only?"
It would be a genuine shock if any of the conservatives vote to uphold the Affordable Care Act, and just as shocking if any of the liberals voted to outlaw it.
But the high court has shocked us before. And liberal Justice Stephen Breyer occasionally has been persuaded to join the conservatives for a 6-3 majority.
The high court can duck the whole problem, too, ruling that a federal law, the Anti-Injunction Act, bars court challenges such as that brought by the states.
The Affordable Care Act has a number of provisions: Insurers are banned from putting lifetime dollar limits on coverage (no sending patients into bankruptcy from long hospital stays); insurers are restricted from putting annual caps on healthcare expenditures; insurers can't discriminate against those who have pre-existing conditions, and many others.
Small businesses also have a stake. One of the challenges accepted by the high court, along with the states', came from the National Federation of Independent Business.
NFIB President and Chief Executive Officer Dan Danner said in a statement: "Only 18 months after its passage, the new healthcare law has been brought to the steps of the Supreme Court by America's small-business owners. For the small-business community, this comes not a day too soon. The healthcare law has not lived up to its promises of reducing costs, allowing citizens to keep their coverage or improving a cumbersome system that has long been a burden to small-business owners and employees, alike. The small-business community can now have hope; their voices are going to be heard in the nation's highest court."
Of course, the law's provisions won't be fully implemented until 2014.
James Sherk, senior policy analyst in labor economics for the Center for Data Analysis at The Heritage Foundation, produced a report this fall saying the Affordable Care Act's requirements on employers will price lower-skilled workers out of full-time jobs.
"President Obama's healthcare law requires employers to offer health benefits to full-time employees," Sherk wrote. "This employer mandate will price many unskilled workers out of full-time employment.
"After paying the new health premiums, the minimum wage, payroll taxes and unemployment insurance taxes, hiring a full-time worker will cost employers at least $10.03 per hour," he said. "Full-time workers with family health plans will cost $13.75 per hour. Employers who hire workers with productivity below these rates will lose money. Businesses employing less skilled workers will probably respond by dumping their employees onto the federally subsidized healthcare exchanges and replacing full-time positions with part-time jobs."
But the focus of the challenges by states' and others is the "individual mandate," the requirement that uninsured Americans who can afford it must buy some kind of health insurance, or face a fine. Currently, about 55 million people in the United States do not have insurance (though the number includes illegal immigrants, who are not affected by the healthcare reform law) and may use visits to hospital emergency rooms as their primary healthcare provider.
The Supreme Court is being asked to decide whether Congress has the power under the Constitution to do this.
Veteran high court reporter Lyle Denniston put it succinctly on the SCOTUSBLOG Web site.
"As the justices review the case filed by 26 states against the Affordable Care Act, they will be examining the core meaning of the Constitution's vertical separation of powers, between national and state governments," Denniston said. "That separation, the Supreme Court said just last term, is a factor contributing to the individual liberty of Americans. The court will hear from one side that the new healthcare law is essential to economic liberty and the basic health of Americans, and from the other side that, as a manifestation of the concentration of power in Washington, the new law itself is a threat to Americans' personal liberty."
The Commerce Clause of the Constitution gives Congress the power "to regulate commerce with foreign nations, and among the several states, and with the Indian tribes." The Necessary and Proper Clause says Congress may do whatever is "necessary and proper" to enforce its Commerce Clause authority and other "enumerated powers" contained in the Constitution.
The states' challenge asks the Supreme Court to decide, "Does the Affordable Care Act's mandate that virtually every individual obtain health insurance exceed Congress' enumerated powers and, if so, to what extent [if any]) can the mandate be severed from the remainder of the act?"
For much of its history, the commerce power of Congress was limited to the regulation of the movement of tangible goods across state boundaries through roads and rivers. That power was vastly expanded in 1942's Wickard vs. Filburn, in which the Supreme Court ruled for the first time the Commerce Clause allowed the regulation of goods produced and consumed solely within a state.
For the next 50 years, Congress used the Commerce Clause to enact a vast number of laws that only had a tenuous connection to interstate commerce.
But in 1995 the Rehnquist Supreme Court unexpectedly limited the scope of the clause. In a 5-4 vote, the justices struck down the federal Gun-Free School Zones Act of 1990, which forbade anyone from knowingly carrying a firearm in a school zone.
In the majority opinion, Chief Justice William Rehnquist said the law was "invalid as beyond Congress' power under the Commerce Clause."
The "possession of a gun in a local school zone is in no sense an economic activity that might, through repetition elsewhere, have ... a substantial effect on interstate commerce," the opinion said.
It added: "To uphold the government's contention that [the law] is justified because firearms possession in a local school zone does indeed substantially affect interstate commerce would require this court to pile inference upon inference in a manner that would ... convert congressional Commerce Clause authority to a general police power of the sort held only by the states."
Rehnquist said the Supreme Court had identified three broad categories "of activity that Congress may regulate under its commerce power ... : Congress may regulate the use of the channels of interstate commerce. ... Second, Congress is empowered to regulate and protect the instrumentalities of interstate commerce, or persons or things in interstate commerce, even though the threat may come only from intrastate activities. ... Finally, Congress' commerce authority includes the power to regulate those ... activities having a substantial relation to interstate commerce ... i.e., those activities that substantially affect interstate commerce."
A second major blow to congressional commerce power came in 2000's U.S. vs. Morrison when the same five-justice majority struck down provisions of the federal Violence Against Women Act.
A woman who said she had been raped by two other students at Virginia Polytechnic Institute filed suit for damages under the civil provisions of the federal act. But the Rehnquist majority said the civil provisions of the act "cannot be sustained under the Commerce Clause or section 5 of the 14th Amendment," which allows Congress to use legislation to enforce "the constitutional guarantee that no state shall deprive any person of life, liberty, or property, without due process or deny any person equal protection of the laws."
However, in 2005's Gonzalez vs. Raich a couple of conservatives apologetically joined the four-member liberal bloc to rule 6-3 that Congress had the authority to regulate home-grown quantities of prescribed marijuana under its commerce power.
The ruling did not invalidate California's medical marijuana law, but meant that someone charged under federal drug laws could not use state law as a defense.
Three of the five-member majority justices in Lopez and Morrison -- conservative Justices Scalia and Thomas, and especially moderate Justice Anthony Kennedy -- are still serving on the high court.
The other two are gone, but their successors are equally conservative.
Chief Justice John Roberts Jr. replaced Rehnquist after the old chief died of cancer in 2005. Roberts is a former Rehnquist clerk.
Justice Samuel Alito replaced retired Justice Sandra Day O'Connor in 2006.
As a federal appellate judge in Philadelphia before ascending to the Supreme Court, Alito questioned the use of the Commerce Clause in congressional regulation of machine guns, and even its use in the enactment of environmental laws such as the Clean Water Act and the Endangered Species Act.