Security precautions were extraordinary for tennis — SWAT teams on the hotel roof and motorcades that never stopped at red lights — and the fear of attack felt real enough that the United States coach, Dennis Ralston, sidelined Harold Solomon in part because he was Jewish. It was one more challenge heaped on the team facing a contest on red clay, a slow and less familiar surface to the Americans and their lone star, Stan Smith.

Even before the Munich attack, Ralston said he had been warned not to take the team to Romania by Neale Fraser, the coach of Australia’s Davis Cup team, which played in Bucharest in the summer of 1972. Fraser told Ralston that his match had been stolen by partisan line calls and cheating.

“You can’t win because they won’t let you,” Ralston recalled Fraser telling him. “You have no idea what you’re getting into.”

But much bigger forces were propelling the United States toward Bucharest. In the late 1960s and early 1970s, Romania and the United States had a cautious alliance that was crucial during the cold war. The United States saw Romania, and its leader, Nicolae Ceausescu, as a wedge to split the Soviet bloc. Ceausescu had shown himself independent of the Soviet Union by refusing to join other Eastern bloc countries in severing diplomatic ties with Israel after the Six-Day War in 1967. A year later, he did not support the Soviet invasion of Czechoslovakia. The United States and Western European countries gave Romania large loans and trading privileges, allowing it to join GATT in 1971 and the I.M.F. a year later, the first Eastern European country to do so.

Another benefit was that Ceausescu had relations with the Chinese government and was perceived as one conduit, along with Pakistan, for Nixon to quietly forge what would become the signature legacy of his foreign policy. One of Nixon’s early foreign policy trips was to Romania.