Masterful.(The Years of Lyndon Johnson: Master of the Senate )

The Years of Lyndon Johnson: Master of the Senate By Robert A. Caro. Alfred A. Knopf, 1,040 pages, $35.00

THE YEAR 1952 WAS A POTENTIALLY dangerous one for the NATO alliance. Western European nations were fearful of Soviet aggression and their leaders were hoping for strong assurances that the United States remained committed to their security.

The congressional debate in Washington was not reassuring. In the U.S. Senate that spring and summer; isolationists were ganging up, as usual, on President Harry Truman's foreign-aid program, vying to see who could slash the most from the $7 billion he had requested for European NATO members. The House had cut $1 billion. Dwight Eisenhower, the just-retired NATO commander, ominously warned that deeper cuts might cripple the alliance. But the Senate's isolationists, led by Republicans Robert Taft of Ohio and Herman Welker of Idaho, were undeterred. "We've already poured $75 billion down a rat hole and still are losing people by the millions to Communism," Welker complained as he proposed cutting another half-billion dollars.

As a key vote neared, the conservatives, due to heavy absences among Northern Democrats and moderate-to-liberal Republicans, appeared to have the numbers to impose their cuts: Forty one of the 81 senators still in Washington that week supported the deep reductions called for by Welker and Louisiana's Russell Long. To the beleaguered Senate majority leader, Democrat Ernest McFarland of Arizona, the situation was hopeless. What the Senate needed, Newsweek magazine suggested, was "a minor miracle."

Just as all hope appeared to have vanished, the 43-year-old majority whip of the Senate, Lyndon Johnson of Texas, developed an idea that his biographer Robert A. Caro suggests may have saved the NATO alliance. As Caro describes the scene in Master of the Senate, the freshman from Texas strode into the chamber with a brilliant plan to salvage Truman's foreign-aid program. Instead of persuading senators to change their votes, Johnson's creative mind perceived another way to win: Get rid of a sufficient number of opposing votes to ensure a victory for Truman. That, he concluded, could only be done by using a maneuver known as a "live pair."

A live pair occurs when a senator refuses to cast a vote out of deference to an absent senator who would have voted the other way. The two non-votes cancel each other and negate the impact of the senator's absence. It is a quaint and arcane practice (and still used in both houses of Congress). Born of senatorial courtesy and decorum, the practice suddenly became, in Johnson's hands, an effective parliamentary weapon. After Senate leaders spent the night contacting absent …