FILE - This Oct. 18, 2012 file photo shows Edith Windsor interviewed at the offices of the New York Civil Liberties Union, in New York. Windsor sued the government in November 2010 because she was told to pay $363,053 in federal estate tax after her partner of 44 years, Thea Spyer, died in 2009. The federal Defense of Marriage Act defines marriage as "a legal union between one man and one woman," and that's what the Internal Revenue Service follows when it comes to federal income taxes. AP Photo/Richard Drew, File)

Associated Press
FILE - This Oct. 18, 2012 file photo shows Edith Windsor interviewed at the offices of the New York Civil Liberties Union, in New York. Windsor sued the government in November 2010 because she was told to pay $363,053 in federal estate tax after her partner of 44 years, Thea Spyer, died in 2009. The federal Defense of Marriage Act defines marriage as "a legal union between one man and one woman," and that's what the Internal Revenue Service follows when it comes to federal income taxes. AP Photo/Richard Drew, File)
FILE - This Oct. 18, 2012 file photo shows Edith Windsor interviewed at the offices of the New York Civil Liberties Union, in New York. Windsor sued the government in November 2010 because she was told to pay $363,053 in federal estate tax after her partner of 44 years, Thea Spyer, died in 2009. The federal Defense of Marriage Act defines marriage as "a legal union between one man and one woman," and that's what the Internal Revenue Service follows when it comes to federal income taxes. AP Photo/Richard Drew, File)