The Rev. William M. Baxter, center, former rector of St. Mark’s Episcopal Church in Washington, escorts President and Mrs. Lyndon B. Johnson after services in March 1966. (UPI photo)

Very late on the night of Friday, Nov. 22, 1963, maybe early in the morning of Nov. 23, the telephone rang in the Capitol Hill home of the Rev. William M. Baxter, rector of St. Mark’s Episcopal Church in Southeast Washington.

The Secret Service was on the line. President Lyndon B. Johnson would be at St. Mark’s for the Sunday morning worship service that week, the caller said. Hours earlier, Johnson had taken the presidential oath of office aboard Air Force One in Dallas following the assassination of President John F. Kennedy.

What had looked like a routine pre-Thanksgiving service to Rev. Baxter suddenly became a historic event, the focal point, if only for a minute, of the global media spotlight. Rev. Baxter, who died Aug. 20 at 90, would be preaching not to his usual congregation of a few hundred, but to the world.

“What I would say to the President?” Rev. Baxter was quoted as having said in “Building Church,” a book written 40 years after the fact by St. Mark’s members George Meng and Joellen Hayden. “Something that was bound to be spread nationwide. . . . I had to prepare something special.”

By Saturday night, Rev. Baxter had rewritten his sermon.

The next morning, Johnson, his wife, two daughters and several Cabinet members showed up a few minutes before the service began. Riflemen lined the roof of the Library of Congress annex across Third Street from St. Mark’s.

Secret Service agents lined the interior walls of the nave. Police were everywhere. A firetruck stood by in case the decrepit church furnace malfunctioned — as it often had. A police detachment burst in on a Sunday school class with orders that no one was to enter or leave until the president’s safety could be ensured.

From his pulpit that morning, Rev. Baxter declared, “We forget that our government is man-made and therefore perishable. Because our way of life is man-made, it is not enduring. . . . We will say prayers for you, Lyndon, our brother, and beseech God to give you . . . the courage and the humility to exercise the powerful responsibilities that fall upon you.”

The sermon is preserved in the National Archives.

After the service, the new president and his family would remain for about a half-hour, sipping coffee, shaking hands and exchanging greetings. Then, moments after presidential assassin Lee Harvey Oswald was assassinated in Dallas, Johnson was spirited away by the Secret Service, for fear that there might be a plot afoot to assassinate the new president.

That was not Johnson’s first Sunday at St. Mark’s during Rev. Baxter’s ministry, nor would it be the last. Johnson had attended Baxter’s services since his days as Senate majority leader, and he continued to do so throughout his presidency.

He showed up one Sunday when an intern seminarian was preaching, and he did not hide his displeasure that Rev. Baxter was not in the pulpit. It then became standard policy that the church office notify the White House on those Sundays when the preacher was someone other than Rev. Baxter.

“ ‘I’d become an Episcopalian but I’m a member of another church. It’s bad politics to shift churches,’ ” Rev. Baxter said the president told him. “LBJ never was a regular attendee. He was an occasional attendee. I went to Camp David two or three times. They helicoptered me there and I had services with the Cabinet and their guests and the president,” he was quoted in “Building Church.”

William MacNeil Baxter was born Oct. 5, 1923, in Halifax, Nova Scotia. He grew up in Newton Centre, Mass., and graduated in 1945 from Amherst College in Massachusetts.

A badly broken leg when he was growing up kept him out of military service during World War II. After attending Virginia Theological Seminary in Alexandria, he was ordained an Episcopal priest in 1951.

He came to St. Mark’s on Capitol Hill in 1954 as the leader of an aging and dwindling congregation, earmarked for closure by the Episcopal bishop of Washington. Rev. Baxter began a program of recruitment and revitalization.

Dance became a part of the liturgy. Dramatic productions by the likes of T.S. Eliot and Tennessee Williams were performed in the chancel. Around the Capitol Hill neighborhood, he distributed fliers inviting “all seekers . . . interested pagans, bored Christians,” skeptics, agnostics and nonbelievers to try St. Mark’s.

He paid scant attention to such church traditions as limiting communion to baptized Episcopalians. Anyone qualified for bread and wine at Rev. Baxter’s church.

When Capitol Hill church-shoppers showed up for the first time, he went the extra mile — literally — to entice them back, walking home with them after a Sunday service.

One of the new members was Harry C. McPherson Jr., a Texas-born lawyer on Johnson’s Senate staff who lived on Capitol Hill. One Sunday, McPherson brought along Lady Bird Johnson, who later came with her husband.

During his presidency, Johnson often brought Cabinet officers and other high officials to St. Mark’s. One of his guests was Adlai E. Stevenson, who was then the U.S. ambassador to the United Nations. At the coffee hour after the worship service, according to “Building Church,” it seemed that everyone in the predominantly liberal congregation wanted to talk with Stevenson, while the president was being ignored. “I had to organize people to talk to him,” Rev. Baxter said.

One Sunday, Rev. Baxter recalled, “The president left church through the side door and looked around at the bare dirt and pitiful grass out there. He told Lady Bird that her churchyard looked like Hell and needed some trees. And she said, ‘Then do something about it. This church doesn’t have money for things like that.’ So he pulled out a fistful of bills and told me to buy some trees.”

Several cherry trees were subsequently planted in the churchyard.

In 1966, Rev. Baxter resigned from St. Mark’s, telling the authors of “Building Church” that he felt he was preaching the same sermons he had preached before and needed a new challenge. He became director of public affairs for the Peace Corps. When Johnson’s presidency ended in 1969 he left government service and in 1970, co-founded the Marriage and Family Institute, a counseling center.

In 1984, he retired from the Marriage and Family Institute and moved to Maine. There, he was interim rector at a church in Lewiston and a founder of FaithWorks, a nonprofit operation providing flexible work opportunities, training and support for the unemployed.

Survivors include his wife of 67 years, Jean Taylor Baxter of Scarborough, Maine; four children, Graeme Baxter and Gary Baxter, both of Washington, Rebecca Owen of Briarcliff Manor, N.Y., and Anne Baxter of New York; seven grandchildren; and two great-granddaughters.

Rev. Baxter died at a retirement facility in Scarborough. The cause was complications from diabetes and dementia, said Gary Baxter.

As a man of the cloth, Rev. Baxter preached a message that how life is lived is more important than church attendance, and he sponsored education programs aimed at encouraging men and women to be honest and direct with each other and themselves. He could be abrupt and confrontational.

“The church is the place to take the truth and tell the truth,” he said.