Howard Baker, who became widely known for questioning President Richard Nixon about the Watergate scandal, died Thursday at age 88. Here are five things to know about his career, which spanned several decades and earned him the respect of Republicans and Democrats alike.

THE FAMOUS QUOTE: While Baker was serving as vice chairman on the Senate committee probing the June 1972 break-in at the Democratic headquarters and the cover-up by Richard Nixon's administration, he asked the president: "What did the president know and when did he know it?" It sharply brought the focus onto Nixon in the Watergate scandal, which ultimately derailed his presidency.

A LONG CAREER: Baker served 18 years in the Senate, earning respect from colleagues in both parties and the nickname "the Great Conciliator." But he also served as Ronald Reagan's chief of staff for a time, and as ambassador to Japan from 2001 to early 2005.

PRESIDENTIAL ASPIRATIONS: Baker was mentioned frequently as presidential material and ran for the office in 1980. He had an eye on another run in 1988 and called his job as Senate majority leader "the second-best job in town, only second to the presidency." But he never ran for president again, instead taking over as Reagan's chief of staff in 1987.

POLITICAL PEDIGREE: Baker had numerous political connections: His father, Howard H. Baker Sr., served in Congress for more than a decade. His first wife, Joy, was the daughter of a U.S. senator. And his second wife, Nancy Landon Kassebaum, was also a U.S. senator.

NOT EXACTLY A KODAK MOMENT: Although he enjoyed photography and carried a camera anywhere he went, Baker took no photos during the Watergate hearings. "I felt that it was beneath the dignity of the event," he said years later. "It turned out the event had no dignity and I should have taken pictures."