John Kerry has handsomely passed another test on the course to the White House. Once again - just as in Vietnam, in his tight Senate re-election race in 1996, and in the primaries this year - the complicated man from Massachusetts delivered when it counted. Mr Kerry is never the most arresting speaker. But on Thursday evening, when he delivered the most important speech of his life to accept the nomination of his party, he delivered one of the best speeches of his life.

John Kerry has handsomely passed another test on the course to the White House. Once again - just as in Vietnam, in his tight Senate re-election race in 1996, and in the primaries this year - the complicated man from Massachusetts delivered when it counted. Mr Kerry is never the most arresting speaker. But on Thursday evening, when he delivered the most important speech of his life to accept the nomination of his party, he delivered one of the best speeches of his life.

It is easy to cavil at the details. Mr Kerry said next to nothing about Iraq. His economic proposals were swathed in generalities. To many non-Americans, many of the trappings of the night will have come across as simplistic symbolism. But but modern-day conventions are showcases, not stages for the great debates of the age. With its heavy emphasis on national security, and its repetitious references to strength and values, this could have been the speech of a Republican nominee, and in a normal year the liberal wing of the Democratic party might not have stood for it. But this is not a normal year. Democrats are united as never before in their desire to evict George W Bush from the White House. If Mr Kerry chose to steal Republican clothes to achieve that end, then so be it. Far more important, he seemed relaxed and comfortable in himself.

Non-Americans will be encouraged by his promise to turn over a new leaf in US foreign policy, working more closely with allies and listening to the opinions of others. The Americans who will vote in the election this autumn saw a candidate who indubitably looks like a president and a commander-in-chief. They will also have gained some idea of John Kerry the man, another central goal of the week. By all these yardsticks, the convention was a resounding success.

Even so, this election remains wide open. However intoxicating or uplifting, a single speech never made a presidency, and while the traditional post-convention "bounce" may propel the Kerry/Edwards tandem into a clear lead, the Republicans have their chance to correct matters when they gather in New York next month. Mr Kerry began this week in a statistical dead heat with Mr Bush. Come Labor Day in early September, when the candidates turn into the final straight, they may well be neck and neck again.

In the end, matters could be settled by outside events. A clear improvement in the economy, an improvement on the ground in Iraq or a major success against al-Qa'ida (perhaps the capture of Osama bin Laden?) could tip the balance in favour of Mr Bush. Continuing chaos in Iraq, or a new terrorist strike, could sweep away the President's claim to be the man best able to keep America safe. If a single "internal" moment proves decisive, it is more likely to be the first of the autumn debates between Mr Kerry and Mr Bush.

As they left Boston, the party faithful were convinced they had listened to the next president of the United States. Far more important, some of those undecided voters, fewer in number in this polarised election year but who, nonetheless, will decide the outcome, may have felt the same.