( CNN ) -- Former U.S. Sen. Howard Baker , a one-time towering political figure in Washington who also served presidents and famously asked during the Watergate scandal what Richard Nixon knew and `` when did he know it , '' has died . He was 88 . A Tennessee Republican , Baker made his political mark over four decades , serving as majority leader and also ran for president in 1980 . Baker 's former press secretary , Tom Griscom , confirmed that he died on Thursday . A statement released by Baker 's wife , former Sen. Nancy Kassebaum , and his two children from his first marriage , Darek Baker and Cynthia ( Cissy ) Baker , said his death was a `` time of sorrow and also a time for the celebration of a remarkable life . '' Senate Minority Leader Mitch McConnell said he would be remembered `` with fondness by members of both political parties . '' Baker was first elected to the Senate in 1966 and led the chamber from 1981-85 . He was Reagan 's chief of staff from 1987-88 , and was ambassador to Japan under President George W. Bush . President Barack Obama said in a statement that Baker 's unofficial role as the `` Great Conciliator '' had `` won him admirers across party lines , over multiple generations , and beyond the state he called home . '' Former President George H.W . Bush said Baker was `` adept at listening to the other guy state their position as he was at articulating his own . '' CNN Chief Political Analyst Gloria Borger said Baker thrived an era when Democrats and Republicans often compromised to get things done in Washington . `` He was one of those senators who could walk across the aisle , cut deals and he was respected on both sides , '' Borger said . `` Today in the Republican Party , that would be taken as a negative . '' Former first lady Nancy Reagan said in a statement that she and her husband had `` the greatest respect '' for Baker 's dedication to service . `` Howard was one of Ronnie 's most valued advisers , his integrity and ability to create cooperation between the Congress and the White House was unparalleled , '' she said . `` Most importantly , though , he was a good and trusted friend . '' Baker also played a key role in the Watergate investigation that led to the downfall of President Richard Nixon . As the vice chairman and ranking Republican of the investigation into Nixon 's connection to the 1972 break-in at the Democratic National Committee headquarters in Washington , Baker famously asked `` what did the President know and when did he know it . '' People we 've lost in 2014 . CNN 's Kevin Bohn contributed to this report .
Baker died on Thursday . He was 88 . He was a former majority leader , presidential candidate , and White House chief of staff . Baker excelled in an era of compromise , known as a conciliator .