(CNN) – The U.S. Supreme Court will rule at 10 a.m. ET Thursday on 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, 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."