Battle Over Obama Health Law Reaches High Court The monumental fight over a health care law that touches all Americans and divides them sharply comes before the Supreme Court on Monday. The justices will decide whether to kill or keep the largest expansion in the nation's social safety net in more than four decades. Two years and three days after President Barack Obama signed into law a health care overhaul aimed at extending medical insurance to more than 30 million Americans, the high court begins three days of hearings over the law's validity. The challenge from 26 states and a small business group puts the court smack in the middle of a heavily partisan fight over the president's major domestic accomplishment and a presidential election campaign in which all his Republican challengers oppose the law. If upheld, the law will force dramatic changes in the way insurance companies do business, including forbidding them from denying coverage due to pre-existing medical conditions and limiting how much they can charge older people. The law envisions that insurers will be able to accommodate older and sicker people without facing financial ruin because of its most disputed element, the requirement that Americans have insurance or pay a penalty. Another major piece of the law is an expansion of the Medicaid program for low-income Americans that will provide coverage to more than 15 million people who currently earn too much to qualify. By 2019, about 95 percent of the country will have health insurance if the law is allowed to take full effect, the Congressional Budget Office estimates. Reams of court filings attest that the changes are being counted on by people with chronic diseases, touted by women who have been denied coverage for their pregnancies, and backed by Americans over 50 but not yet old enough to qualify for Medicare, who face age-inflated insurance premiums. Republicans are leading the fight to kill the law either by the court or through congressional repeal. They say the worst fears about what they derisively call "Obamacare" already have come to pass in the form of higher costs and regulations, claims that the law's supporters dispute. GOP presidential candidates all promise to repeal it if elected. "Obamacare has already proven unpopular and unaffordable," House Speaker John Boehner, an Ohio Republican, said on the law's second anniversary. The White House says it has little doubt the high court will uphold the law, and that even its opponents will eventually change their tune. "One thing I'm confident of is, by the end of this decade, we're going to be very glad the Republicans termed this 'Obamacare,' because when the reality of health care is in place, it's going to be nothing like the kind of fear-mongering that was done," said David Plouffe, a senior adviser to the president, said Sunday in an interview with ABC's "This Week with George Stephanopoulos." Polls have consistently shown the public is at best ambivalent about the benefits of the health care law, and that a majority of Americans believe the insurance requirement is unconstitutional. The administration's public education campaign has come under strong criticism from its allies who say the White House has been timid in the face of relentless Republican attacks.