The U.S. Supreme Court Thursday upheld the constitutionality of the Affordable Care Act, the health care law that President Obama signed in March 2010. Here's a look at key moments in the law's history:

February 24, 2009 -- In a joint session to Congress, -- 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 Obama 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 of health policy and industry experts to discuss the development of health care 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.

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August 15, 2009 -- During the August recess, Obama travels in support of the bill. Tea Party members and conservatives -- During the August recess, Obama travels in support of the bill. Tea Party members and conservatives lash out against the bill at town halls. 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 legislation, dies, jeopardizing Senate Democrats' 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 sole compromise health care bill to date.

October 13, 2009 -- The Senate Finance Committee approves Baucus' landmark bill, the America's Healthy Future Act.

November 7, 2009 -- The House of Representatives -- 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 Democrat, -- Senator Ben Nelson, a conservative Democrat, becomes the 60th vote needed to pass the Senate version of the health care bill.

December 24, 2009 -- The Senate -- The Senate passes its health care bill 60-39.

January 17, 2010 -- Obama -- Obama stumps for Martha Coakley in a tight Massachusetts Senate race against Scott Brown to replace Kennedy. Brown had pledged to vote against Democratic health care efforts.

January 19, 2010 -- Brown -- Brown wins the special election , jeopardizing the health care legislation.

February 25, 2010 -- Obama holds a -- 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," needing only 51 votes, to pass the health care bill.

March 21, 2010 -- The -- The Senate passes its version of the bill, sending the legislation to Obama for his signature. 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 -- Obama signs the health care bill into law.

August 12, 2011 -- The 11th Circuit Court of Appeals -- 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 -- 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, -- 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 -- The Supreme Court begins three days of oral arguments over the constitutionality of the law.

June 28, 2012 -- The Supreme Court rules that the individual mandate portion of the health care law may be upheld within Congress' power under the taxing clause.