First tenure in the Kentucky Senate

In 1972, Baker was elected to the Kentucky Senate.^[5] At the end of the legislative session, the Capitol Press Corps recognized him as its Outstanding Freshman Senator.^[9] In 1974, Baker was the lone vote against a Senate resolution honoring Martin Luther King Jr., explaining that he thought the Civil Rights Movement had pushed for too much too soon.^[10]

Baker received the Kentucky Council on Crime and Delinquency Outstanding Service Award in 1975.^[11] In 1976, he failed to unseat Congressman William H. Natcher, a popular Democratic incumbent, but by capturing 40% of the vote, he came as close as any candidate in the previous 20 years to defeating Natcher.^[2][12]

In 1976, 1978, and 1979, Baker was chair of the Senate's Republican caucus.^[13] He advocated a 1976 overhaul of the state judicial system proposed by Governor Julian Carroll.^[4] He was also the lone Republican to vote against a bill allowing public schools to post copies of the Ten Commandments in their classrooms; Baker explained that he thought the law was unconstitutional.^[3] In 1978, he was designated the most outstanding orator in the Kentucky Senate by the Capitol Press Corps.^[9]

Service in the Reagan administration and legislative interim

On June 15, 1981, Baker resigned his seat in the state senate to accept President Ronald Reagan's appointment as assistant general counsel for International Affairs in the Department of Defense.^[3] He held that position until 1983, and upon leaving the position, was presented the Department of Defense Outstanding Public Service Award.^[11]

On his return to Kentucky, Baker co-chaired Reagan's re-election campaign in Kentucky's 2nd congressional district.^[14] He was mentioned as a possible running mate for Jim Bunning in Bunning's 1983 gubernatorial campaign, but reportedly declined the offer.^[15] Instead, he challenged incumbent state senator Joe Lane Travis, who had won a special election to finish Baker's senate term, in the 1984 Republican primary election.^[15] During the campaign, Baker attacked Travis because he was not a lifelong Republican, while Travis countered that Baker had abandoned his constituents to take a position in the federal government.^[3] Baker lost the primary by 24 votes.^[16]

In August 1985, Baker was named to the Prichard Committee for Academic Excellence, and he was elected as the group's secretary in 1987.^[17][18] Baker was chosen secretary of the newly formed Kentucky Advocates for Higher Education in October 1985.^[19] He also considered running for lieutenant governor in 1987 on a ticket with Larry Forgy.^[20] After Forgy decided not to make the race for governor, Baker began to consider his own gubernatorial bid, but ultimately, he decided there was not enough time to mount a credible campaign and declined to run for any office in 1987.^[20]

Return to the state senate

Baker again challenged Joe Lane Travis for his senate seat in 1989.^[21] During the campaign, Baker complained that the Kentucky Republican Senatorial Committee gave $1,000 to Travis' campaign, saying the group's funds "should be used to support the Republican nominee and not used to favor one candidate over another in the Republican primary".^[21] Travis questioned why Baker, in his previous time as a legislator had never sponsored a major bill; Baker answered that he had worked to get members of the Democratic majority to sponsor or co-sponsor bills he favored in order to get them passed.^[16] Baker countered that Travis had been a "reflexive 'no' vote" in the Senate and that his support of proposals with little change of succeeding, such as a right-to-work law and shoring up the state workers' compensation system by moving Kentucky coal miners to the federal black lung disability system amounted to ideological grandstanding.^[16] Baker won the primary election by 112 votes and faced Democrat Larry Freas, the mayor of Franklin, in the general election.^[22][23]

Freas touted his successful 11-year tenure as mayor, during which he saved the city over $300,000 by turning many services over to private companies, constructed a new city hall as well as new water- and sewage-treatment plants, and reduced unemployment.^[23] Baker countered that Freas has also put several of his family members on the city's payroll, pleaded guilty to drunk driving in January 1986, and filed for bankruptcy in April 1987 following the failure of his restaurant business.^[23] Baker also said Freas had not been visible enough on the campaign trail.^[23] Baker carried all seven counties in the district and won the election by over 12,000 votes.^[24] Following the 1989 legislative session, Baker's was one of three names recommended to President George H. W. Bush by Senator Wendell H. Ford as potential replacements for Sixth Circuit Court of Appeals Judge Pierce Lively, who assumed senior status.^[25]

After the Kentucky Supreme Court declared Kentucky's entire public education system unconstitutional due to inequalities in funding for local districts, Senate President John "Eck" Rose appointed Baker as the only Republican legislator on the committee charged with creating a system that would meet the court's definition of constitutionality.^[26] John Rogers, the Republican floor leader in the Senate, objected that he was not consulted about Baker's appointment, that Republicans were underrepresented on the committee, and that Baker – despite his previous legislative service – was considered a freshman legislator.^[26] Baker said he believed more Republicans would be appointed to the committee when he agreed to serve.^[26] The committee presented the Kentucky Education Reform Act to the legislature in 1990, and Baker was one of only three Republicans who voted for it.^[7] Baker was awarded the Louisville-Jefferson County Crime Commission Legislator of the Year Award in both 1990 and 1992.^[11] He was unopposed for re-election in 1992.^[27]

In 1990, Baker reversed an earlier position, joining Gerald Neal, the only African-American member of the Senate, in advocating for a bill to make Martin Luther King, Jr. Day a state holiday.^[10] Baker apologized for his earlier stand against the Senate honoring King, saying simply, "I was wrong."^[28] A Lexington Herald-Leader columnist wrote of Baker's speech, in which he recounted that his family had owned slaves until his great-grandfather freed them in the 1820s, that it "set such a high moral tone for the Senate that no one else spoke – and no one voted against the King holiday."^[28]

Baker represented the National Conference of State Legislatures on trips to China, Japan, and the Soviet Union.^[4] In 1995, at the request of the United States Information Agency, he advised the parliaments of Tomsk and Nizhny Novgorod on writing constitutions.^[2] Later that year, he received the William H. Natcher Award for Outstanding Public Service from the Barren River Area Development District.^[11] He served in the Senate until 1996.^[5]

Kentucky Supreme Court

State Representative Richie Sanders announced he would challenge Baker for his Senate seat in 1996 after legislative redistricting made it unlikely he could win re-election to his seat in the House.^[29] On April 8, 1996, Democratic Governor Paul E. Patton announced his appointment of Baker to the Kentucky Supreme Court, replacing Justice Charles H. Reynolds, who died in January.^[30] Baker's appointment left Democrat Jake Dickinson as the perceived favorite to defeat Sanders and win Baker's seat in the Senate.^[30] Baker resigned his seat in the Senate on April 15, the final day of the legislative session, and was sworn in as a justice an hour later.^[31]

Four men, including Baker, announced their candidacy for the November special election to fill the remainder of Reynolds' term.^[32] The other candidates included Kentucky Court of Appeals Justices John Miller and Joseph Huddleston and William S. Cooper.^[32] Baker finished third in the special election with 30,278 votes; Cooper won the seat, garnering 33,670 votes to Huddleston's 32,137 and Miller's 26,592.^[33] Each candidate won by a large margin in his home county, but Baker, from Barren County, cut into Huddleston's margin in neighboring Warren County, while low overall voter turnout in Daviess County hurt Miller.^[33] During the campaign, fellow justice Joseph Lambert told Baker that he spent too much time writing opinions and not enough time campaigning.^[2]