COLUMN LEFT : A Compelling, Credible Critic Steps Out Front : Bush’s snubbing of domestic opinion on the gulf makes him vulnerable to Sam Nunn in 1992.

Having executed a masterpiece of inter national coalition-building, President Bush’s failure to recognize that democracies cannot fight wars without strong public and legislative support has been incomprehensible. It was against this backdrop of careful international consultation that Bush failed to consult with Sen. Sam Nunn of Georgia, chairman of the Senate Armed Services Committee and the Democrats’ leading expert on defense and military matters, before increasing force levels in the Persian Gulf. The long-term result may be that Bush has gotten himself a formidable opponent for 1992.

If you ask Nunn whether he is running for President, he says, “No plans, no desires,” and moves on to the next topic. But speculation is growing that he will run. It is not fueled by trips to Iowa and New Hampshire, meetings with fund-raisers, speeches about America’s future or any of the other usual signals. Rather it is the fact that in the month following Bush’s surprise decision to increase troop levels, the United States has, in Nunn’s words, “gone from the original military mission of deterring further Iraqi aggression, defending Saudi Arabia and enforcing the embargo to a military mission of liberating Kuwait.” Nunn has become the leading critic of Bush’s policy in the gulf, as unlikely a leader of an anti-war movement as can be found. He bears no resemblance to the anti-military, isolationist, blame-America-first crowd that inhabits the left wing of the Democratic Party.

In the current instance, it is precisely Nunn’s conservative, pro-military background that makes him the Democrats’ most compelling critic of the Administration. When Nunn takes a strong position on a defense-related question, he is given an unusual amount of attention.

Nunn emphasizes the fact that military action in the gulf is justified, that he was fully behind what he refers to as Bush’s “strategy No. 1,” which was to defend Saudi Arabi against further Iraqi aggression while allowing sanctions to work to force Iraq from Kuwait. But Bush’s changed strategy has for the past month had Nunn posing questions that need answers: Why is the liberation of Kuwait and the high-casualty ground war it entails in America’s strategic interests? What are the long-term consequences for our relations with the Arab world if Arabs are defeated by Westerners? What evidence is there that the embargo is not working? How can we sustain this level of manpower in the gulf and still be prepared for military emergencies in other parts of the world? And, most fundamentally, has Bush put us in a position where logistics dictate policy? “If we can’t sustain those forces,” says Nunn, “then it will drive the decision to war rather than having the decision made by deliberate policy.”

The recent Senate hearings addressed but did not answer many of Nunn’s questions. But in the broader context of the 1992 elections it is worth considering what the past month says about Bush’s presidency. His reluctance to explain and justify his actions to America or, at the very least, its elected representatives in Congress, reveals a contempt for public opinion and domestic consensus. If Bush is vulnerable, one leading reason will be the belief that public communication and consensus are incidental to, not central to, governing.

The line of capable Democrats who can challenge Bush on domestic policy is long. But interest in Nunn comes from the fact that he stands alone among potential Democratic presidential contenders in his ability to mount a credible challenge to Bush as commander in chief. Americans want their President to protect American interests, values and lives; candidates who cannot convey the mastery needed to do all three simultaneously cannot win.

The gulf crisis has had, from the beginning, the capacity to make or break Bush’s presidency. Assume a short, victorious war with few casualties and Bush could be Maggie Thatcher after Britain’s victory in the Falklands--an unbeatable candidate riding a wave of national pride. Assume any outcome that is less clear and there will be a challenge.

Nunn’s authority to lead the assault on Bush’s military and foreign policies could help minimize his weaknesses in quest of the Democratic nomination. Although he has recently adopted a pro-abortion-rights position, and although his hard-core conservative profile on domestic issues has taken on a decidedly more liberal tone, Nunn can expect a hard time from the traditional liberals who dominate the nomination process. But if he can manage the Democratic primaries, Nunn will be a formidable candidate--perhaps the only one who can challenge Bush on his own turf and win.