Arlen Specter, a longtime U.S. senator from Pennsylvania, died on October 14, 2012, at his home in Philadelphia, Pennsylvania, from complications of non-Hodgkins lymphoma—a type of cancer that he had been battling since 2005. He was 82 years old. Specter shocked politicians on both sides of the aisle in 2009, when he announced he was switching to the Democratic Party after registering as a Republican for more than four decades (since 1965). At a news conference held in 2009, Specter explained his decision to switch parties: "As the Republican Party has moved farther and farther to the right, I have found myself increasingly at odds with the Republican philosophy and more in line with the philosophy of the Democratic Party," he said. Specter, born on February 12, 1930, in Wichita, Kansas, to Russian immigrants, got his start in politics after becoming a top staff member of the Warren Commission in 1964. There, he investigated the assassination of President John F. Kennedy, and helped develop the "single-bullet theory," which suggested that both JFK and Texas Governor John Connally—who was shot and killed in June 1993—had been wounded by the same bullet. He was a registered Democrat at the time. Not long after, Specter switched to the Republican Party, and ran as a Republican for the Philadelphia District Attorney seat. He won, and served as D.A. until 1974. Then, in 1980, Specter was elected to represent Pennsylvania in the U.S. Senate. He was re-elected to his Senate seat four times thereafter, in 1986, 1992, 1998 and 2004. In the late 1990s, Specter criticized the Republican Party for its impeachment of President Bill Clinton—Specter claimed that Clinton had not received a fair trial—and worked for the reauthorization of the Patriot Act, which the Senate passed in July 2005. In February 2005, Specter announced that he had been diagnosed with an advanced form of non-Hodgkin's lymphoma, a type of cancer. Continuing to work in the Senate while undergoing chemotherapy, Specter ended treatment in July 2005. However, in April 2008, the lymphoma returned, forcing the senator to undergo a second round of chemotherapy. Specter went back into remission in July 2008. Beginning in the early 2000s, Specter played a major role in encouraging medical research. After receiving the news of Specter's death on October 14, 2012, President Barack Obama issued the following statement: "Arlen Specter was always a fighter. From his days stamping out corruption as a prosecutor in Philadelphia to his three decades of service in the Senate, Arlen was fiercely independent—never putting party or ideology ahead of the people he was chosen to serve. He brought that same toughness and determination to his personal struggles, using his own story to inspire others. When he announced that his cancer had returned in 2005, Arlen said, 'I have beaten a brain tumor, bypass heart surgery and many tough political opponents and I'm going to beat this, too.' Arlen fought that battle for seven more years with the same resolve he used to fight for stem-cell research funding, veterans health, and countless other issues that will continue to change lives for years to come. Michelle and I send our thoughts and prayers to Joan and the rest of the Specter family." Specter was survived by his wife, Joan Levy, sons Shanin and Stephen, and his four grandchildren, Silvi, Perri, Lilli and Hatti.