Playing dirty could cost candidates the greatest prize of all

SOME say it is unfair to have quoted the member of Barack Obama's campaign team who blurted out "Hillary Clinton is a monster" to a Scotsman journalist and immediately claimed it as off the record as well as off the cuff. But don't believe that anyone who is anywhere near a presidential hopeful at this stage in the game ever says anything that isn't carefully scripted. Even the denial that it was ever said will have been worked on by a team of advisers before the off-the-cuff

Call me cynical, but planting seeds of doubt in the minds of the electorate then denying that such seeds reflect the views of the candidate is an age-old trick. Teams of people have based their careers on deciding who is going to make a so-called "gaffe" and at what stage of the campaign, who will deny it and how vociferously.

There is a stage in any election where things can start to get a bit nasty, or interesting, depending on your viewpoint, on both sides. Hillary Clinton's latest television campaign advert seems to suggest that Barack Obama isn't capable of protecting America's sleeping children. The ad, and if you haven't caught it it's currently showing on YouTube alongside a thousand different parodies, suggests that if a crisis call came in the middle of the night to the Oval Office, Hillary is the only one with the experience to deal with it. The pictures of sleeping children over the insistent soundtrack of a ringing telephone, a thunderous musical score and the voiceover with the gravitas and underlying menace of Orson Welles can't help but leave the impression that Barack Obama would let your children be taken by evil child-snatchers in the night. It could be made more frightening if they used the Jaws music, but only just.

At no point does it actually say that Barack is the babysitter from hell, nor do the pictures expressly suggest it, but by carefully manipulating the feel of horror films and every parents' worst nightmare, that is the impression we are left with. The pitch has to be just right for this kind of suggestion to work. The best examples tap into what the electorate already suspect about a candidate, and it must only be a suggestion – if it comes in ladlefuls it can have the reverse effect.

Hillary Clinton being called a monster seems to have trod the line successfully, reinforcing a commonly held idea. Reaction from America on The Scotsman website is along the lines of "Tell us something we didn't know", and the revelation that she is considered brutally ambitious is unlikely to bring much surprise to those who would or wouldn't have voted for her anyway. The "3am While Your Children are Sleeping" advert seems to have landed a punch on Barack Obama's campaign, judging by the shot in the arm Hillary got from voters on Tuesday.

Just as you need to be cynical about such tactics, they do make the spectacle more interesting, especially as it is a neck-and-neck fight for the Democratic nomination. If the two candidates sink to mudslinging, however sophisticated and subtle, they may wound the eventual victor so severely that he or she doesn't have the strength to take on the match-fit and rested John McCain. Most of Europe doesn't want to see a Republican in the White House for another term, but despite the millions paid to the masters of spin who manage the news, only a tiny margin of US citizens ever change the way they vote.

Which means it shouldn't take that much mud to stick to either Hillary or Obama in this semi-final to land a fatal blow for the Democrats in the final.