The Rockefeller Commission had finished its investigation of the CIA, and the House inquiry was enmeshed in a quarrel over the makeup of the committee. That left Senator Frank Forrester Church in sole possession of the hottest potato in Washington these days: did American Presidents know about or authorize assassination attempts against foreign leaders?

"My friends have said this investigation is like walking through a minefield," says the 50-year-old Democratic senior senator from Idaho. His Select Committee on Intelligence may hold televised hearings this summer and, among other duties, he must prevent their becoming a media carnival like the Watergate inquiry.

Already Church's assignment has brought him into conflict with Vice-President Nelson Rockefeller. "His report may represent just the tip of the iceberg," Church says. Some of Rockefeller's recommendations for curbing the CIA's illegal domestic activities were good, he says, "but have the ring of 'go forth and sin no more.' This is an empty admonishment. We must place in law specific prohibitions."

Church criticizes Rockefeller for avoiding "the most sensitive issue, political assassination." Yet when the senator said his committee had found no evidence to link ex-Presidents with plots to murder foreign leaders, Rockefeller publicly suggested that John Kennedy might have known about such intrigue.

The senator supported Rockefeller for Vice-President (Mrs. Church opposed him) but seems less than happy about it now. "I think people tend to be impressed because he is Nelson Rockefeller. He isn't judged as other men are. His record as governor of New York leaves much wanting. He gets by by being Rockefeller."

The senator's interest in the Vice-President transcends his handling of the CIA investigation. Church's own hearings could catapult him into the front line of contenders for the Democratic presidential nomination. The prospect clearly quickens his pulse—but he insists he will consider it "only after this investigation is behind me."

From the day he walked onto the Senate floor in 1957, looking a decade younger than his 32 years, Church has been known as one of its more serious, high-principled members. He was among the first to oppose the Vietnam war and it caused him grief back in Idaho.

"Even my wife, Bethine, didn't agree with me," says Church. "She was especially worried about my break with the Johnsons." (LBJ contemptuously referred to him as "Frank Sunday School.") Winning his wife over, Church went home to fend off a recall petition which charged him with treason. In the end, only 159 voters signed it.

Even as a youth Church seemed to make the right moves. At 16, he won the American Legion's national Americanism oratorical contest. He earned an A.B. and and LL.D. at Stanford. In 1949, the year before he received his law degree, Church, who by then had married his high school sweetheart, Bethine Clark, whose father and uncle had been governors of Idaho, was told he had a fatal cancerous tumor. Surgery and massive radiological treatments saved his life. "It gave me an entirely new outlook—I was willing to take the risk, the plunge into politics. Life doesn't usually yield up chances a second time."

In his first plunge into politics at 28, he lost in Republican Boise for a seat in the state legislature, but four years later his wife's contacts in the Democratic party paid off. To this day Bethine remains his best campaigner.

For 18 years the Churches, who have two sons, Chase, 17, and Forrest, 26, a Unitarian minister, have lived quietly in the same Bethesda split-level. Occasionally, along with members of his staff, the family will rough it at their cabin near the Catoctin Mountain, Md., where Church organizes "highly violent games of volleyball," says Mrs. Church. She brags that her six-foot husband is in good shape, has a 34 waist, and weighs only 175, despite his jowly photographs. "Every pound he puts on goes right to his 'chipmunk cheeks,' " she says.

It promises to be a long summer for Frank Church, and he may find himself drawing a reluctant bead on his own party. "There is no moral justification for any agency of the U.S. to murder in times of peace," he says with the indignant rhetoric which characterizes most of his public pronouncements. "The American President must never become a glorified Godfather."