Howard Baker, who spent nearly two decades in the U.S. Senate before serving as chief of staff for President Ronald Reagan, has died at his Tennessee home. He was 88.

Baker became famous during the 1973 Senate hearings into the Nixon administration's Watergate scandal with his question: "What did the president know and when did he know it?"

A moderate Republican, he was skilful at establishing alliances with politicians on both sides of the aisle.

Former Secretary of State James A. Baker III (no relation), who served with Baker in the second Reagan administration, described the Tennessean as "the quintessential mediator, negotiator and moderator."

As Senate majority leader between 1981-1985, he was instrumental in getting Reagan's tax cuts passed.

Later, as White House chief of staff, he helped the administration weather the Iran-Contra scandal.

Wed in 1951 to Joy Dirksen, daughter of Sen. Everett Dirksen, Baker was left a widower in 1993. Three years later he married again, to former Sen. Nancy Landon Kassebaum.

He is survived by Kassebaum, two children from his first marriage, Darek Baker and Cynthia "Cissy" Baker, four grandchildren, a sister and a half-sister. EFE