The U.S. Supreme Court will rule this month on the constitutionality of the Affordable Care Act , the health-care reform law that President Obama had signed in March 2010. Here's a look at key moments in the law's history:
Feb. 24, 2009 -- In a joint session to Congress, President Obama says: "So let there be no doubt: Health care reform cannot wait, it must not wait, and it will not wait another year."
March 5, 2009 -- The White House holds its first health care summit.
April 21, 2009 -- Senate Finance Committee Chairman Max Baucus and Ranking Member Chuck Grassley hold the first of three roundtables bringing together health policy and industry experts to discuss the development of health care reform legislation.
July 15, 2009 -- The Senate's Health, Education, Labor and Pensions Committee passes The Affordable Health Choices Act. The bipartisan bill includes more than 160 Republican amendments accepted during the month-long mark-up, one of the longest in Congressional history.
July 31, 2009 -- The bill is reported out of the House Committee on Energy and Commerce by a vote of 31 to 28.
August 15, 2009 -- During the August recess, Obama goes on the road in support of the bill. Angry Tea Party members and conservatives lash out against the bill at town halls. President Obama battles a false rumor that the legislation includes "death panels" that could decide whether people live or die.
August 26, 2009 -- Sen. Edward "Ted" Kennedy, a leading proponent of health care reform, dies. That risks Senate Democrats losing their 60-seat filibuster-proof supermajority.
September 29, 2009 -- The Senate Finance Committee rejects two amendments to include a government-run public health insurance option in the only compromise health care bill so far.
October 13, 2009 -- The Senate Finance Committee approves Baucus' landmark health reform bill, the America's Healthy Future Act.
November 7, 2009 -- The House of Representatives passes a version of the sweeping health care bill by a vote of 220-215.
December 19, 2009 -- Senator Ben Nelson, a conservative Democratic, becomes the 60th vote needed to pass the Senate version of the health care bill.
December 24, 2009 -- The Senate passes its health care bill 60-39.
January 17, 2010 -- Obama stumps for Martha Coakley in a tight race against Scott Brown to replace Kennedy. Brown had pledged to vote against Democratic health care efforts.
January 19, 2010 -- Brown wins the special election, jeopardizing the health care legislation.
February 25, 2010 -- Obama holds a televised heath care summit with leaders from both parties to explain the health care bill.
March 11, 2010 -- In a letter to Senate Minority Leader Mitch McConnell, Majority Leader Harry Reid says Democrats will use 'reconciliation' to pass the health care bill, needing only 51 votes.
March 21, 2010 -- The Senate passes its version of the bill, sending the legislation to Obama's desk to be signed. A separate package of changes expanding the reach of the measure also passed the House over unanimous GOP opposition, and will be taken up by the Senate.
March 23, 2010 -- Obama signs the health care bill into law.
August 12, 2011 -- The 11th Circuit Court of Appeals rules that parts of the law are unconstitutional.
November 8, 2011 -- The U.S. Court of Appeals in Washington rules that the law is constitutional.
November 14, 2011 -- The Supreme Court agrees to hear a legal challenge to the law after 26 states, led by Florida, petitioned the high court.
March 26, 2012 -- The Supreme Court begins three days of oral arguments over the constitutionality of the law.