The US Presidential Elections: US advertising blitz goes down the tubes: Television has lost its punch in the election battle, writes David Usborne

IF IT is true that a single, smart-bomb advertisement can determine the outcome of a US election, then it has yet to be aired in this year's campaign. Spots there are aplenty, especially negative ones, but no real knock-outs.

It may even be that 1992 will go down as the race when the power of advertising in US presidential politics was finally put into context. For several reasons, not least a zealous commitment by the press to monitor for falsehoods, campaign commercials this time seem not to be driving the race.

The contrast with previous campaigns is striking. In 1988, George Bush's victory over Governor Michael Dukakis was helped by the 'Willie Horton' television spot - paid for, incidentally, by Bush supporters, not by the campaign itself - about a black prisoner who raped and assaulted a white couple after being released on parole in Mr Dukakis' state.

Four years earlier, President Reagan was helped back to the White House by a widely acclaimed advertising splurge of sentimental visuals and aeroplane music that went under the up-beat slogan, 'It's Morning in America'.

It is not that the parties are not spending money. Mr Bush and Mr Clinton will have poured about dollars 70m ( pounds 40.9m) of their funds into radio and television advertising by 3 November. Meanwhile, Ross Perot will spend several millions of his personal fortune on his own airwave blitz, which includes a series of 30-minute paid-for programmes on network television.

In themselves, the advertisements seem to have the right ingredients, especially a series of biting attacks by the Bush camp on Mr Clinton. The most recent, released last Sunday to coincide with the first televised presidential debate, shows a single image - that of an April cover of Time magazine with a negative photograph of Mr Clinton and the headline 'Why Voters Don't Trust Clinton'. (Time has complained bitterly about the advertisement and has demanded its withdrawal.)

Among other Bush productions, one attempts to exploit doubts about Mr Clinton's intentions on taxes, speculating on how much extra money in taxation families on different income levels may pay under a Clinton presidency (a tactic reminiscent of Tory campaign ads in the British election).

The wittiest Bush offering so far, conceived to play up inconsistencies in Mr Clinton's positions, shows two candidates side by side but with their faces smudged out for anonymity. Each man has expressed opposing views, the narrator says, on matters such as the Gulf war and the Vietnam draft. Revealing, finally, that both men are one and the same, it concludes: 'One of these candidates is Bill Clinton. Unfortunately, so is the other'.

With so much ground to make up, Mr Bush has the most need of a boost from his advertising efforts. So far though, according to the evidence of daily polls, none of these spots has yet made much impression. Perhaps voters have made up their minds on the candidates and are not open to any persuasion. Particularly, it seems that they do not share with President Bush the doubts he has about Mr Clinton, whether over patriotism or taxation.

The most important change, though, is in the attitudes of the American press, which still suffers guilt for what it believes was the soft ride it gave candidates, and especially Mr Bush, in the overwhelmingly negative 1988 campaign. As each radio and television advertisement debuts, it is minutely dissected in Adwatch newspaper columns and Truth Squad features on television news programmes. Mr Bush's spot about the possible tax increases promised by Mr Clinton drew immediate tut- tuts right across the media.

The importance of paid-for commercials is perhaps being diluted by the sudden opening of the airwaves to the candidates themselves. For the first time, the candidates have been given a virtual open door to the breakfast news programmes and widely viewed chat shows, like CNN's Larry King Live.

Why take notice of packaged, undoubtedly distorted, 30-second commercials, when you can see the product itself, day after day, on our favourite morning discussion programmes, voters seem to be asking themselves.