A former governor, university president and secretary of education, Mr. Alexander has modeled himself on Senator Howard R. Baker Jr., another Tennessee Republican, who turned against President Richard M. Nixon during Watergate. Mr. Baker, who died in 2014, introduced Mr. Alexander to Mr. McConnell in 1969, when Mr. Alexander was an aide in the Nixon White House and Mr. McConnell was a legislative assistant to a Kentucky senator.
Few friendships in the Capitol have been as enduring as theirs. Today Mr. McConnell calls Mr. Alexander “my best friend in the Senate.” But Mr. Alexander said he did not give Mr. McConnell — whom he described, aptly, as “a person of few words” — advance notice of his vote.
“I know what he thinks, and he knows that is not the way to influence my decisions,” he said.
Yet Mr. McConnell did not really have to ask. Although Mr. Alexander was lumped in with three other Republicans — Susan Collins of Maine, Lisa Murkowski of Alaska and Mitt Romney of Utah — who had expressed openness to witnesses, it was clear early on that he was unlikely to vote to include them.
Those close to him say he does not relish shaking things up.
“I think that Lamar has been able to successfully navigate the ins and outs of the new administration because Lamar is very wise in how he shares, when he shares, any disagreement or policy difference he might have with the administration,” said Tom Griscom, a close friend of Mr. Alexander who worked as Mr. Baker’s press secretary. “He’s not looking to be out on the front edge of it.”
Another close friend, Tom Ingram, who ran Mr. Alexander’s Senate races and served as his chief of staff, said he was not surprised by Mr. Alexander’s decision. He said Mr. Alexander was troubled by what he regarded as a highly partisan impeachment process in the House, and wanted to assure that the Senate gave it thorough consideration, which was why he had expressed openness to witnesses.
“Knowing the reverence he holds for the presidency — the office, not the person — and for the Senate process and how seriously he takes impeachment, it was going to have to be very clear in his mind that the offense clearly fit the high bar set in the Constitution.”