After graduating from Tennessee Law College he was admitted to the Tennessee bar in 1949. A member of the Republican Party Baker was elected to the Senate in 1966.
The phone number of E. Howard Hunt was found in address books of the burglars. Reporters were now able to link the break-in to the White House. Bob Woodward, a reporter working for the Washington Post was told by a friend who was employed by the government, that senior aides of President Richard Nixon, had paid the burglars to obtain information about its political opponents.
In 1972 Richard Nixon was once again selected as the Republican presidential candidate. On 7th November, Nixon easily won the the election with 61 per cent of the popular vote. Soon after the election reports by Bob Woodward and Carl Bernstein of the Washington Post, began to claim that some of Nixon's top officials were involved in organizing the Watergate break-in.
Frederick LaRue now decided that it would be necessary to pay the large sums of money to secure their silence. LaRue raised $300,000 in hush money. Anthony Ulasewicz, a former New York policeman, was given the task of arranging the payments.
Hugh Sloan, testified that LaRue told him that he would have to commit perjury in order to protect the conspirators. LaRue was arrested and eventually found guilty of conspiring to obstruct justice. He was sentenced to three years in jail but only served four months before being released.
Richard Nixon continued to insist that he knew nothing about the case or the payment of "hush-money" to the burglars. However, in April 1973, Nixon forced two of his principal advisers H. R. Haldeman and John Ehrlichman, to resign. A third adviser, John Dean, refused to go and was sacked. On 20th April, Dean issued a statement making it clear that he was unwilling to be a "scapegoat in the Watergate case".
On 7th February, 1973, the Senate voted to create a Select Committee on Presidential Campaign Activities. Sam Ervin was appointed chairman of this committee. Baker was a member of the committee and hearings took place between 17th May to 7th August and 24th September to 15th November.
William Colby was eventually given the Pennington file. On 28th June, 1974, he reported to Baker: "The results of our investigation clearly show that the CIA had in its possession, as early as June, 1972, information that one of its paid operatives, Lee R. Pennington, Jr., had entered the James McCord residence shortly after the Watergate break-in and destroyed documents which might show a link between McCord and the CIA."
In 1975, Frank Church became the chairman of the Select Committee to Study Governmental Operations with Respect to Intelligence Activities. This committee investigated alleged abuses of power by the Central Intelligence Agency and the Federal Bureau of Intelligence. Baker became a member of this committee. As a result of his investigations Baker became a critic of the Warren Commission.
The committee also reported that the CIA had withheld from the Warren Commission, during its investigation of the assassination of John F. Kennedy, information about plots by the Government of the United States against Fidel Castro of Cuba; and that the FBI had conducted a counter-intelligence program (COINTELPRO) against Martin Luther King and the Southern Christian Leadership Conference.
The Mafia boss, Sam Giancana was ordered to appear before the Select Committee to Study Governmental Operations with Respect to Intelligence Activities. However, before he could appear, on 19th June, 1975, Giancana was murdered in his own home. He had a massive wound in the back of the head. He had also been shot six times in a circle around the mouth. At the same time Jimmy Hoffa, another man the committee wanted to interview, also disappeared. His body was never found.
Johnny Roselli was also due to appear before Church's committee when he was murdered and in July 1976 his body was found floating in an oil drum in Miami's Dumfoundling Bay. Jack Anderson, of the Washington Post, interviewed Roselli just before he was killed. On 7th September, 1976, the newspaper reported Roselli as saying : "When Oswald was picked up, the underworld conspirators feared he would crack and disclose information that might lead to them. This almost certainly would have brought a massive U.S. crackdown on the Mafia. So Jack Ruby was ordered to eliminate Oswald."
As a result of Church's report and the deaths of Sam Giancana, Jimmy Hoffa and Johnny Roselli, Congress established the House Select Committee on Assassinations in September 1976. The resolution authorized a 12-member select committee to conduct an investigation of the circumstances surrounding the deaths of John F. Kennedy and Martin Luther King.
Baker served as minority leader (1977-1981) and majority leader (1981-85). He retired from Congress in 1985 and served as chief of staff to President Ronald Reagan (1987-88). In 2001 Baker was appointed as United States Ambassador to Japan.