Thomas Joseph Ridge is an American politician and author who served in the George W. Bush administration as the Assistant to the President for Homeland Security from 2001 to 2003 and as the United States Secretary of Homeland Security from 2003 to 2005. He was the first person to hold either office. A member of the Republican Party, he previously served in the United States House of Representatives from 1983 to 1995 and as the 43rd governor of Pennsylvania from 1995 to 2001.

George W. Bush's tenure as the 43rd president of the United States began with his first inauguration on January 20, 2001, and ended on January 20, 2009. Bush, a Republican from Texas, took office following his narrow Electoral College victory over Democratic incumbent vice president Al Gore in the 2000 presidential election, in which he lost the popular vote to Gore by 543,895 votes. Four years later, in the 2004 presidential election, he narrowly defeated Democrat nominee John Kerry, to win re-election. Bush served two terms and was succeeded by Democrat Barack Obama, who won the 2008 presidential election. Bush is the eldest son of the 41st president, George H. W. Bush.