The Supreme Court did not rule on the constitutionality of President Obama's health care law Monday, pushing the announcement of the decision to Thursday morning.
The decision is among the most closely watched in decades. As a political matter, the case tests Obama's signature achievement as president, the Affordable Care Act.
The ruling could also impact millions of Americans' access to health insurance, which the law expanded through Medicaid, the future creation of health care exchanges for private insurance and the provision allowing adult children to remain on their parents' plans until age 26.
The Court could deal with the law in any number of ways. It could invalidate or sustain the law as a whole, or strike down provisions -- such as the individual mandate to purchase health insurance -- and leave most of the rest of the law in place. It could also punt on ruling on the law at all, or void the Medicaid expansion.
The court heard three days of argument in March over the case.
Former President Theodore Roosevelt champions national health insurance as he unsuccessfully tries to ride his progressive Bull Moose Party back to the White House. (Photo by Topical Press Agency/Getty Images)
President Franklin D. Roosevelt favors creating national health insurance amid the Great Depression but decides to push for Social Security first. (Photo by Keystone/Getty Images)
Roosevelt establishes wage and price controls during World War II. Businesses can't attract workers with higher pay so they compete through added benefits, including health insurance, which grows into a workplace perk. (Photo by Hulton Archive/Getty Images)
President Harry Truman calls on Congress to create a national insurance program for those who pay voluntary fees. The American Medical Association denounces the idea as "socialized medicine" and it goes nowhere. (Photo by Keystone/Getty Images)
John F. Kennedy makes health care a major campaign issue but as president can't get a plan for the elderly through Congress. (Photo by Keystone/Getty Images)
President Lyndon B. Johnson's legendary arm-twisting and a Congress dominated by his fellow Democrats lead to creation of two landmark government health programs: Medicare for the elderly and Medicaid for the poor. (AFP/AFP/Getty Images)
President Richard Nixon wants to require employers to cover their workers and create federal subsidies to help everyone else buy private insurance. The Watergate scandal intervenes. (Photo by Keystone/Getty Images)
President Jimmy Carter pushes a mandatory national health plan, but economic recession helps push it aside. (Photo by Central Press/Getty Images)
President Ronald Reagan signs COBRA, a requirement that employers let former workers stay on the company health plan for 18 months after leaving a job, with workers bearing the cost. (MIKE SARGENT/AFP/Getty Images)
Congress expands Medicare by adding a prescription drug benefit and catastrophic care coverage. It doesn't last long. Barraged by protests from older Americans upset about paying a tax to finance the additional coverage, Congress repeals the law the next year. (TIM SLOAN/AFP/Getty Images)
President Bill Clinton puts first lady Hillary Rodham Clinton in charge of developing what becomes a 1,300-page plan for universal coverage. It requires businesses to cover their workers and mandates that everyone have health insurance. The plan meets Republican opposition, divides Democrats and comes under a firestorm of lobbying from businesses and the health care industry. It dies in the Senate. (PAUL J. RICHARDS/AFP/Getty Images)
Clinton signs bipartisan legislation creating a state-federal program to provide coverage for millions of children in families of modest means whose incomes are too high to qualify for Medicaid. (JAMAL A. WILSON/AFP/Getty Images)
President George W. Bush persuades Congress to add prescription drug coverage to Medicare in a major expansion of the program for older people. (STEPHEN JAFFE/AFP/Getty Images)
Hillary Rodham Clinton promotes a sweeping health care plan in her bid for the Democratic presidential nomination. She loses to Obama, who has a less comprehensive plan. (PAUL RICHARDS/AFP/Getty Images)
President Barack Obama and the Democratic-controlled Congress spend an intense year ironing out legislation to require most companies to cover their workers; mandate that everyone have coverage or pay a fine; require insurance companies to accept all comers, regardless of any pre-existing conditions; and assist people who can't afford insurance. (Alex Wong/Getty Images)
With no Republican support, Congress passes the measure, designed to extend health care coverage to more than 30 million uninsured people. Republican opponents scorned the law as "Obamacare." (Mark Wilson/Getty Images)
On a campaign tour in the Midwest, Obama himself embraces the term "Obamacare" and says the law shows "I do care." (BRENDAN SMIALOWSKI/AFP/Getty Images)