The Soviets, who had been monitoring the airlift’s performance, apparently understood what the numbers meant. On April 25, 1949, the Soviet news agency Tass signaled that the blockade might end. Allied and Soviet negotiators reached agreement on May 4. The blockade was officially lifted on May 12, 1949.
## The Diplomacy Beside the Logistics
The Berlin Airlift was a logistical achievement, but it was also a political one, and the two dimensions were inseparable.
General Lucius Clay, who administered the American occupation zone in Germany, argued from the beginning that abandoning Berlin would be catastrophic for American credibility in Europe. His cables to Washington in June 1948 pushed the Truman administration toward the airlift rather than withdrawal. Clay understood that the Soviet blockade was a test: if the United States and Britain backed down, the credibility of their commitment to European security would be damaged in ways that would be difficult to repair.
President Harry Truman authorized the airlift and reinforced the American position by sending B-29 bombers to bases in Britain. The B-29 was the aircraft that had dropped atomic bombs on Japan, and its deployment to Britain was a signal about the seriousness of American resolve. The bombers did not carry nuclear weapons, but their presence was understood in its context.
The formation of NATO, the North Atlantic Treaty Organization, coincided almost exactly with the end of the blockade. The treaty was signed on April 4, 1949, eight weeks before the blockade was lifted. West Germany was established as a formal state approximately two weeks after the blockade ended. The Berlin crisis and its resolution contributed directly to the institutional architecture of the Cold War in Europe.