BILL Clinton's campaign pledge to lift the US military's ban against homosexuals quickly was swept away last week by a tidal wave of criticism and controversy. Though the new President - who must feel as if he hit the ground running backwards - has not retreated from his basic commitment, what was supposed to be a fait accompli is suddenly an open question. The question is: should avowed homosexuals be allowed to serve in the armed forces, and, if so, will their acknowledged presence require revised rules of conduct and special accommodations, literal or figurative? When candidate Clinton first staked out his position on gays in the forces during the primaries, it barely caused a ripple. For one thing, he had company. Indeed, all the Democratic contenders for the White House were in agreement. Even Ross Perot, devout believer in the Rockwellian America adorning his office walls, swallowed his intolerance and supported removing the ban. And when Republican attempts to ignite a ''holy war'' of social values backfired, who could blame Mr Clinton for failing to foresee the fire-storm of protest that would engulf his first executive effort? The outrage expressed by the religious right and Republicans in Congress was predictable. But Mr Clinton was also blind-sided: negative public opinion swelled on radio talk-shows and in calls to Congress; the Joint Chiefs-of-Staff lodged their unanimousopposition in a closed-door meeting with the President; Senator Sam Nunn, a Democrat and by far the most influential voice in Congress on military matters, sided with the generals; and even Les Aspin, Mr Clinton's new Defence Secretary, was clearly uncomfortable trying to market his boss's plan to lift the prohibition. The public, the military and Democrats in Congress - how did Mr Clinton offend so many so fast? While the flood of phone calls to the White House and Congress last week was overwhelmingly opposed to allowing gays to serve openly in the military, most polls suggest that Americans are evenly divided on the issue. (Women are far more tolerant than men.) There are at least two reasons for the odd discrepancy between the polls and the calls. Many of the anti-gay messages sent to Washington originate from technologically sophisticated and well-funded conservative organisations that have pioneered the technique of barraging elected officials with calls, telegrams and letters. In an era when opinion polls have taken the weight of instant referendums - Republican senators opposed to the President rattled off phone-call ratios in a press conference last week as proof of how Americans feel - such tactics are effective. The problem is that they do not necessarily reflect opinion. (There is another problem: we elect leaders to lead, not to follow.) The polls, however, are probably skewed too. The precepts of political correctness make many people reluctant to express what they fear are socially unacceptable views. Asking, for example, ''Should gays be banned from serving in the military?'' is almost the same as asking, ''Are you a homophobe?'' Few will admit it. Mr Clinton's problems in dealing with the military are legion, beginning with his weak credibility as a commander-in-chief because he has never served in the forces and missed the draft in the Vietnam War. Furthermore, top military officers truly believe that allowing gays to serve openly will wreck morale, undermine recruiting, provoke resignations, increase the spread of AIDS and generally corrode ''good order and discipline'', in the words of the chairman of the Joint Chiefs-of-Staff Colin Powell. These arguments, of course, sound eerily familiar: all of them (except fear of AIDS) were advanced when Harry Truman ordered the racial integration of the military in 1948. No one disputes that there are already thousands, probably tens of thousands, of gays in the military. More than 12,000 have been discharged in the last decade. The generals opposed to the administration's policy think homosexual soldiers should remain in the closet. If they want to join the army, navy, air force or Marines secrecy is the price of admission. In Congress, Mr Clinton fell foul of his own inexperience. Senior senators, especially Mr Nunn, were not pleased that the President tried to act unilaterally, so they gave him a lesson in humility and power-sharing. It was, in part, the turf battle between the legislative and executive. The White House lost. When the President realised that Congress might pass a veto-proof codification of the ban if he abolished it by executive order, he had to settle for a fig-leaf compromise. Mr Clinton would wait six months before taking action to consult Congress and the military. In the meantime, the current rules are to stay in effect with a couple of changes, albeit significant ones: new recruits will no longer be asked if they are homosexual or bisexual, as has been the practice until now; and armed service members who are gay, while still subject to discharge proceedings, cannot be thrown out altogether. Ending the ban against gays in uniform is, for Mr Clinton, more than just another campaign promise to a special interest group, a reward payback for services rendered. It is a matter of civil rights on a par with moves to halt racial and gender discrimination. He is right, but the fear and loathing of homosexuality is rooted in society, and will not abate any more quickly than has the evil of racial prejudice. Nor will it be inexpensive politically. Ask Harry Truman.