JOHN KERRY is urging Democrats to restrain from vilifying President Bush and instead spend this critical convention week rallying around his upbeat pitch for power.

Delegates were gathering in a heavily-fortified Boston for tonight’s opening session of the party’s quadrennial convention with the grassroots united against their opponent as rarely before. But the party’s presidential challenger has sent word to speakers that he wants attacks on Mr Bush kept to a minimum.

Kerry aides were working to ensure the goal of the nominating convention should instead be to loosen Mr Kerry’s stiff public image and present him to the country as an experienced optimist ready to inhabit the Oval Office.

The move is something of a gamble in that visceral hatred of Mr Bush has so far been the driving force of the Democratic campaign.

“Do people feel it?” asked Mr Kerry in an eve-of-convention interview with The New York Times. “Sure. I mean it’s an honest emotion. And there’s a great deal of energy in the Democratic base.”

But Mr Kerry and his advisers want to use their big televised moment — when millions of Americans tune into the contest for the first time — to be positive. Seven out of 10 voters say they do not know enough about the Massachusetts Senator, and this week is Mr Kerry’s big chance to fill in the gaps.

Most of the speeches building up to Mr Kerry’s acceptance of the nomination on Thursday will be hymns of praise to Mr Kerry’s heroic Vietnam service, his largely-unknown stint as a tough criminal prosecutor, and his 20 years of Senate experience, particularly in foreign affairs.

Mr Kerry said he wanted to avoid the convention degenerating into a tirade against Mr Bush, however much that might delight the rank and file. Senior aides are seeking to vet the speeches of prime-time performers to tone down their rhetoric.“I want this to be a positive affirmation of why I’m running for President and what I want to do as President,” said Mr Kerry.

Mr Kerry goes into the convention in a close run with Mr Bush in the polls. A Time magazine poll yesterday gave him 46 per cent to Mr Bush’s 43 per cent.

But an Associated Press analysis said Mr Bush was well-placed to win 25 states, giving him 217 votes in the decisive electoral college. Mr Kerry looks good in 14 states, earning him 193 electoral college votes. A total of 270 is required for victory .

Time showed 53 per cent think it is time for someone else to be President, against 43 per cent who think Mr Bush deserves to be re-elected. But voters still prefer Mr Bush on issues such as national security and the War on Terror, one reason the Kerry campaign will be emphasising their candidate’s 20 years on the Foreign Relations Committee.

“I think I can do a better job than George Bush,” he said in his interview. “I can fight a more effective War on Terror. I can make America safer. I will bring allies back to our side.”

Mr Kerry is to arrive in Boston in Wednesday after a six-day tour of cities in battleground states during which he is presenting himself as a “champion for the middle class”, and the best representative of American values.

When the convention ends on Friday he and John Edwards, his running-mate, will embark on a two-week, 21-state “Believe in America” tour, trying to use the post-convention momentum to build a solid lead in the polls.

Boston is bristling with the tightest security ever given to such an event. F-16 fighter jets are continually patrolling the skies, 40 miles of commuter roads are closed every evening, and stations are closed.

Two out of three Bostonians are said to be leaving the city or taking the week off work.

Until now, strong anti-Bush sentiment has driven the election campaign, defining the polarised political landscape.

In the primaries, Howard Dean fuelled his remarkable campaign with a vigorous Bush-bashing platform, before burning out. Since winning the primaries, Mr Kerry has surfed the same wave to raise an extraordinary $185 million, more than four times any previous Democrat.

Mr Kerry said: “My plan is to introduce both myself and the vision I have for the country. But I want to do it in a personal way.”

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