He later served as governor of Arkansas. As governor, he overhauled the state's education system and served as chairman of the National Governors Association. Clinton was elected president in 1992, defeating incumbent Republican opponent George H. W. Bush. At age 46, he became the third-youngest president in history. On September 21, 1996, Clinton signed into law the Defense of Marriage Act (DOMA), which defined marriage for federal purposes as the legal union of one man and one woman; the legislation allowed individual states to refuse to recognize gay marriages that were performed in other states. On September 21, 1996, Clinton signed into law the Defense of Marriage Act (DOMA), which defined marriage for federal purposes as the legal union of one man and one woman; the legislation allowed individual states to refuse to recognize gay marriages that were performed in other states. Paul Yandura, speaking for the White House gay and lesbian liaison office, said Clinton's signing DOMA 'was a political decision that they made at the time of a re-election'.