Iraq in 2006 is not Vietnam. However, the voting public’s despair of the bloodletting puts the Bush administration in the same brittle shape as was the Johnson administration in the summer of 1966.

President Johnson committed America to defeat in Vietnam because he could not imagine a viable exit. “If I send in more men, there’ll be killin’,” Mr. Johnson complained in January 1965; “If I take out men, there’ll be killin’. Anything I do, there’ll be killin’.” One year later, following a pointless Christmas halt of the bombing of North Vietnam, Mr. Johnson could see that not only was the South Vietnamese government a sham, but also that the American public doubted the purpose of the war. Mr. Johnson felt deserted by his dovish Senate colleagues such as Fulbright, Gore, Morse, and Aiken, and he grew suspicious that his hawkish generals would betray him by going over his head to the Congress. “I hope you don’t pull a MacArthur on me,” Mr. Johnson told Mr. Westmoreland.

By springtime, 1966, Johnson was ready to abandon South Vietnam and so ordered McNamara’s Defense Department to plan for a withdrawal within weeks. Soon after, South Vietnam descended into the chaos of sectarian war between Saigon’s forces and Buddhist resistance. Mr. Johnson’s advisers darkened. The ambitious Bobby Kennedy sensed weakness and maneuvered to the left of LBJ to anticipate a negotiated settlement with Communist North Vietnam. Mr. Johnson quipped, “I have no objections to Bobby being the president of this country — I just, by God, want to be president myself.”

In pique at Mr. Kennedy’s gaming, Mr. Johnson nixed withdrawal and the war escalated the more. The Democratic Party espied a risk for the midterm elections. “The American people are concerned about Vietnam,” said one Party wag, “there is a dark void there, and they don’t know exactly where we’re going as a nation.” Soon, the Democrats turned their backs on LBJ on the stump and in the straw polls, preferring Mr. Kennedy to Mr. Johnson 48% to 44% for the presidency in 1968. Election Day was a scary loss of 47 Democratic seats in the House and 3 in the Senate, with exit polls showing Vietnam as the explanation for Republican gains. Two years later, the Democrats tore themselves in two over the war and the reconstructed Richard Nixon claimed the White House. (Find Johnson’s ruin in Randall Woods’ new “LBJ: Architect of American Ambition.”)

The alternative ending for Vietnam in 1966 was for Mr. Johnson to ignore Bobby Kennedy’s junior coup, to shut out the hawks in the Senate and the DoD, and to negotiate with Hanoi to withdraw American military forces by the summer of 1966, creating the sort of failed Vietnamese state that eventually followed the American defeat in 1975. Today, Mr. Johnson would be remembered for the Great Society and Apollo 11.

Are there alternative endings for Iraq? One scenario is to accept that you cannot make a modern nation of the shards of five centuries of colonialism and that a partition into three security blocs, Kurdistan, Shiastan, and Sunnistan, is already accomplished. Another scenario is to accept that Iraq is outflanked by Syria and Iran and that it is already a colony of Teheran. Neither of these outcomes would be unrecognizable to the region or disruptive to the status quo ante at the United Nations Security Council, both would shift the costs of state-building away from American blood and treasure.

Is the Bush administration contemplating withdrawing American military forces from Iraq? How do you hear President Bush’s recent reference to an unseen dispute? “There’s a lot of people — good, decent people — saying withdraw now. They’re absolutely wrong. It would be a huge mistake.” This sounds suggestively as if the Bush administration has reached the same crisis point that the Johnson Administration reached in 1966. This sounds as if the president hears the voices of his own party, his own privy council, telling him that it is wise to begin withdrawing from Iraq before the new Congress sits in January because it may well become a rout afterward.

How did Lyndon Johnson handle the voices of his own party in the summer of 1966? Gathering with the Democratic Senate committee chairs, Mr. Johnson listened to their equivocating and whining about how Vietnam was draining their domestic and foreign commitments, unbalancing the budget, weakening the polls. Mr. Johnson fenced for a time and then attacked. “If you want me out of Vietnam, then you have the prerogative of taking out the resolution under which we are out there now. You can repeal it tomorrow. You can tell the troops to come home. You can tell General Westmoreland that he doesn’t know what he’s doing.”

The Democrats of 1966 did not force their own president’s hand and the result was a revolt that lost the executive. Do the Republicans of 2006 mean to stand by and watch their party suffer the same fate? “A miasma of trouble hangs over everything,” wrote Lady Bird Johnson in her diary in January, 1967. “It is so hard to fight a limited war.”

Mr. Batchelor is host of “The John Batchelor Show” on the ABC radio network.The show airs in New York on 770 AM from 10 p.m. to 1 a.m.