Whatever the wider consequences of Britain's election campaign, it is a relief to be rid of the smiling.
It has been the toothiest election in British history. Mr Blair has unquestionably outsmiled everyone, supported by his wife Cherie; but Ffion Hague, the opposition leader's wife, countered with a gentler, subtler movement of the lips. Only the Chancellor of the Exchequer, Mr Gordon Brown, has maintained his grim-set jaw.
The prominence of the smile is a clear sign that politics is becoming still closer to showbiz. But does it reassure worried voters? The idea of a smiling contest does not really square with the idea of taking government seriously.
Until the last decade, smiling was not a high priority for British politicians - many of whom had bad teeth anyway. Among prime ministers, Churchill always preferred the bulldog look; Harold Macmillan bared his teeth for emphasis, not fun; Harold Wilson never looked really jolly; Edward Heath looked best when scowling; Margaret Thatcher's teeth were always menacing; John Major was the first prime minister to be constantly smiling, which did not do him much good.
It was the Americans who first regarded smiling as essential to politicians, to show that they loved the people. Roosevelt grinned away between his cigarette holder, Eisenhower never stopped beaming, Kennedy outsmiled Nixon, Clinton outsmiled everyone.
The camera played its part in perpetuating the insincere grin, as photographers told their subjects to "say cheese" or "smile please" to force their lips apart, while television compelled all politicians to behave more like actors. The public image became separated from the reality of the private personality.
But there was always a downside to the American smile, associated with salesmen and fraudsters. Before the great crash of 1929, the president of the New York stock exchange, Richard Whitney, had a famous smile that could attract the most sceptical investors: after he was convicted of embezzlement, it was described as "an affair of facial muscles only".
And in Europe, the popularity of the smile has been a relatively new phenomenon - as has been recently discussed in the New York Review of Books. Colin Jones, of Warwick University in England, pointed out that it was odd that "the open-mouthed and toothy smile, which is so much a badge of identity, good health, and beauty in the 21st century, should appear to have no history - or at any rate, no historians". He explained that in 18th century France "the appearance of a living subject's teeth in a painting invariably signified that the person baring her teeth in this way was plebeian or vulgar, lunatic or demented, or else caught expressing some extreme emotion or grand passion".
In European history, the smile has usually been associated with treachery and deception, seduction and trickery. Shakespeare was always wary of smilers. "Where we are, there's daggers in men's smiles," says King Duncan's son in Macbeth; and Hamlet discovers in Act I "that one may smile, and smile and be a villain".
For most of the 20th century, the wide smile was associated with film stars or toothpaste advertisements rather than with politicians. Post-war European statesmen such as de Gaulle, Adenauer and Churchill were not expected to smile as they bore the burdens of the world; and the famous picture of Churchill and Roosevelt smiling with Stalin at Yalta in 1945 rightly aroused suspicions that they were being fooled by him.
Only under the influence of Kennedy and the TV cameras in the 1960s have European politicians felt impelled to bare their teeth.
The mouths have widened and the grins have become broader, until today heads of government are expected to greet each other at the most serious summit as if they were sharing a joke. There is nothing reassuring about any leader laughing off a crisis.
I suspect that the non-smilers will come back into fashion as the recession continues. Mr Gordon Brown has wisely stuck to his grim look, even when he promises generous concessions. And President Bush may have set a new style with his brisk smirk and hurried wave, with a look of "can't you see I'm busy". As Colin Jones suggests, if Tony Blair had been around in the 18th century, "he would almost certainly have been locked away as a demented lunatic".