“At last!” the ghost of President Lyndon Johnson exults, “A biography I like.” Randall B. Woods’s exculpatory book, “LBJ: Architect of American Ambition” (Free Press, 1,024 pages, $35), is notable for a name that never appears: Robert Caro. Johnson’s other major biographer, Robert Dallek, is often cited in this densely documented work, but Mr. Caro is missing from the acknowledgments, and if he appears at all in the notes, all I can say is mea culpa.He is not even present to be dismissed. He is a biographer Mr. Woods dare not bring up.

Why this extraordinary erasure? Is Mr. Caro beneath contempt? Mr. Caro is a journalist who does not claim to be a historian or even a biographer. He calls his books studies in power. Certainly he writes riveting narratives that have sometimes been deemed melodramatic, with Johnson hogging the stage as the evil genius of American politics.The dull Mr. Dallek, on the other hand, is the historian’s favorite and is viewed as more measured.

Mr. Caro does make his way into Mr. Woods’s book in one rather oblique fashion: “Previous biographers have made much of the ‘simple’ patriotism that characterized the environment in which LBJ grew up.” But Mr. Woods holds that this is not so: “Even at nineteen Lyndon realized that the American political system was a process, not a state, that it contained the seeds of social good but also of social evil.” A Texas native himself, Mr. Woods bridles at the patronizing tone he detects in New York biographers like Mr. Caro.

“One of his biographers would dub Johnson ‘Senator Strangelove’ for his Armageddon-like statements” about the necessity of nuclear war with the Soviet Union, Mr. Woods reports as he defends Johnson. “It should be noted that they were the stuff of brinkmanship and massive retaliation, the foreign policy doctrines that would sweep Dwight D. Eisenhower and John Foster Dulles into power in 1952 and keep them there for eight years.” Johnson was no looney, or at least no more looney than his contemporaries.

The notorious 1948 election, in which Johnson became a senator because of a handful of stolen votes — a story that Mr. Caro plays for all its choice chicanery — becomes in Mr. Woods’s narrative another example of extenuating circumstances. Johnson’s opponent, Coke Stevenson, was a reactionary and vote stealer extraordinaire, and Johnson, a Roosevelt New Deal Liberal, deserved to win and probably did win — give or take a few stolen votes. What difference does it make?

For Mr. Woods, Johnson was on the side of angels, even if, at times, he brought himself precariously close to the pit of fire. His nefarious ploys rank well below the perfidy of the Kennedys — no mean vote buyers and stealers themselves — who ridiculed Johnson and never made use of his huge talent while he was vice president. And Bobby! My God, what a thug he is in Mr. Woods’s narrative, jabbing his finger into Hubert Humphrey’s chest, trying to intimidate him into bringing Minnesota into the Kennedy column at the 1960 Democratic Convention.

To be sure, none of LBJ’s faults are skirted in this biography, but they often appear clothed in the perspective of history, i.e., others were just as blameworthy. In this sense, an exculpatory biography can be therapeutic. It is wrong to pin the tail on the Johnson donkey, especially since Johnson was more of a liberal (a good thing to Mr. Woods) than JFK ever was.

Coming from a conservative state, Johnson had to pay his respects to segregationist politics, even though the man himself was no racist, Mr. Woods explains. Indeed, even by the standards of political correctness, Lyndon Johnson’s personal attitudes toward blacks and other minorities are exemplary. The first book he gave to Lady Bird during their courtship was about the evil of Nazi Germany. Johnson understood what was happening to the Jews and helped many of them escape to this country and settle here.

Perhaps the most impressive moment in this biography comes in a passage when Mr. Woods describes Johnson responding to a question from Jim Deakin, a reporter from the “St. Louis Post-Dispatch”:

‘Mr. President, I don’t understand.You didn’t have a very sterling progressive record on civil rights either in the House or in the Senate, and yet here you have thrown the full weight of your presidency behind the civil rights movement. Would you, please sir, explain the contradictions?’ Johnson paused a full thirty seconds before answering. Resisting the temptation to rationalize or to defend his past actions, he said, ‘Well, Jim, some people get a chance late in life to correct the sins of their youth and very few get a chance as big as the White House.’

This is a magnificent moment in American history. President Johnson never treated civil rights as just a political issue. As a senator, yes, he wheedled and compromised. But in the end, civil rights to him was a moral issue, and he did not want his own record or any justification of his record to cloud what was right, now that he had the power to effect major changes.

Mr. Woods also makes a stirring defense of Johnson’s Vietnam policy — not, I would hasten to add, that the president was right about Vietnam, but that his commitment to the war was an integral part of his effort to create a just world rather than a diversion from his domestic policies (his war on poverty and his vision of a Great Society). If he reneged on his commitment to the South Vietnamese, how could Americans, his own people, ever trust him to make good on his promises? Here Mr. Woods makes a signal contribution to Johnson biography and does what a biographer should do: He reconstructs the world as his subject actually saw it and not as the biographer wishes his subject had seen it.

There is an extraordinary irony that anti-Vietnam War liberals ought to contemplate in Mr. Woods’s superb re-creation of Johnson’s thinking. When Walter Lippmann turned against the war, he wrote, “Lyndon Johnson is a complicated human being. There are at least two spirits wrestling within him. One is that of the peacemaker and reformer and herald of a better world. The other is that of the primitive frontiersman who wants to be the biggest, the best, the first, a worshipper of what William James called the bitch-goddess, success.” Lippmann may have been right, but as Mr. Woods shows, Lippmann was not right enough:

Fool! LBJ thought. Could he and the others not see that the cause of domestic reform, especially the fate of the civil rights movement, was inextricably intertwined with the course of the war in Vietnam? If the administration failed to prevent a direct military confrontation with the communist superpowers on the one hand or secure an “honorable peace” in Vietnam on the other, there could only be reaction, not reform, on the home front.

Mr. Woods does not say it, but if anyone destroyed liberalism as a potent political force in this country, it was the antiwar liberals, not Lyndon Johnson.

Whatever qualms I might have about this biography, it gets as close to the man as perhaps a biographer could. Could any biography of Johnson make a better claim for itself?

crollyson@nysun.com