For Gore it is now a question of character

The Democratic convention in Los Angeles is the biggest - and possibly last - opportunity for the party's candidate to make up lost ground

On Thursday night, Vice-President Al Gore must walk on to the platform at the Staples Centre in Los Angeles and give the speech of his life.

On Thursday night, Vice-President Al Gore must walk on to the platform at the Staples Centre in Los Angeles and give the speech of his life.

Success, as he accepts the Democratic nomination, will keep him in the presidential race with a sporting chance of winning. Failure could spell the beginning of the end of his political career, at 52.

To succeed, Mr Gore must must parry the attacks - overt and implied - from the platform of the Republican convention two weeks ago, but he must also present himself as a party leader and president-in-waiting, a superior alternative to George W Bush and his well-drilled, seemingly moderate Republicans.

The last is perhaps the simplest. The policy ideas set out by Mr Bush left gaping holes just waiting for the Democratic nominee to fill. Healthcare, pensions, low pay and the environment, as well as reform of the business-dominated system of political funding, are areas of public concern that Mr Gore can usefully exploit.

He can claim a share of the credit for the US's longest period of economic expansion and cite his eight years' White House experience to support his claim to be a better steward of the country's prosperity into the future. He can also upstage Mr Bush's boast of leading a diverse and inclusive party by having named Joseph Lieberman, an Orthodox Jew, as his running mate.

So far, so good. But Mr Gore's weaknesses lie less in content than in manner and character. From his earliest years as a Congressman from Tennessee, even his supporters had nagging doubts about the mismatch between the scale of his ambition and his political and intellectual abilities. Having attained his party's presidential nomination after two failed attempts, he must now show that there is genuine substance beneath the exaggerated ardour or anger he often displays in his public appearances. Everyone knows he has experience; what they question is whether he has the spine to take the hard decisions and the insight to read the nation's mood.

The Vice-President's intellectual calibre, compared with that of Mr Bush anyway, is not at issue; his political sensitivity and his ability to connect with the voters are. While described universally as delightful and even funny in private, Mr Gore lacks Mr Bush's charm in public. It may be that the presence of his running mate, the far more relaxed and even garrulous Mr Lieberman, will loosen him up. But unless he can make up in gravitas and honesty what he lacks in charisma, he will fare badly by comparison with Mr Bush.

The Governor of Texas, though, is not the only, or even the most threatening, point of comparison. In Los Angeles, Mr Gore has somehow to emerge from the giant shadow of Bill Clinton. Making the move from Vice-President to presidential nominee is always problematical, but Mr Clinton has given Mr Gore an even harder job than Ronald Reagan gave George Bush senior in 1988. Both two-term presidents had an exceptional talent for communicating and an uncanny sense of the national mood. Like Mr Bush with Mr Reagan, Mr Gore will never match Mr Clinton: he lacks his personal magnetism, political instinct and quickness of mind.

Where Mr Gore is worse off than Mr Bush, however, is in the issue of ethics. Mr Clinton bequeaths to Mr Gore the fall-out from White House sleaze and his own scandal.

Against that, Mr Gore can set the solidity of his family. The choice of Mr Lieberman, one of Mr Clinton's earliest critics in the Lewinsky affair, has given him one degree of separation. Mr Clinton's own new apology last week gave him another.

But Mr Gore is not without ethical burdens of his own: his hesitation about condemning Mr Clinton's conduct with Lewinsky is one; the legality of his fund-raising and his equivocation about it is another. Somehow he must allay voters' doubts on these scores.

While planned to look less slick than the Republicans' song-and-dance show of unity and moderation, the Democratic convention has been no less choreographed, and to one end alone: portraying Al Gore as president-in-waiting. The Clintons, Bill and Hillary, will address the convention tomorrow and then leave the West Coast altogether.

There will be no joint Clinton-Gore fund-raising or platform appearance. The remaining three nights will see the progressive reintroduction of Al Gore: family man, caring politician, national leader.