President Obama's speech at the Democratic National Convention marks the official start of a US presidential campaign that will continue unabated until polling day on November 6.
Over the next eight-and-a-half weeks Mr Obama and his opponent, former Massachusetts governor Mitt Romney, will battle it out for the right to lead the world's most powerful country for the next four years.
If Mr Obama wakes up to another four years in the White House on November 7 he will owe former President Bill Clinton an enormous debt. Normally the speeches at US party conventions are of the instantly forgettable, standard boilerplate variety. Not Bill Clinton. Over three-quarters of an hour, twice the time he had been allocated, "Slick Willy" did a far more effective job of making the case for a second Obama term than the president himself did the following night.
As the incumbent, Mr Obama will never be able to recreate the excitement of the 2008 campaign when he became the first African-American to be elected to the White House. However, he has been strangely reluctant to trumpet the very real achievements of his first term, most notably enacting healthcare legislation that had defeated presidents Truman, Nixon and Clinton.
While the provision of near-universal health coverage is something we Europeans take for granted, it has been the Holy Grail of American politics for the past two-thirds of a century. After the failures of his predecessors, it was Mr Obama who got healthcare over the line. For that alone his first term deserves to be remembered.
Mr Obama also deserves credit for overseeing the gradual recovery of the American economy over the past four years. For those tempted to criticise the president's economic record, it is only necessary to cast one's mind back to the autumn, or "fall" as the Americans call it, of 2008 when there was a very real possibility that the entire financial world of the United States would collapse with catastrophic consequences, not just for the US but the entire global economy.
The fact that some of the president's most vociferous critics are concentrated among the ranks of the do-nothing Republicans in the Senate and House of Representatives should also be borne in mind. Turning their backs on the historic American tradition of political compromise they have opposed the president at every turn over the past three-and-a-half years and now seek to blame him for the consequences of their own intransigence.
Despite the extremism of large parts of the Republican Party, its presidential candidate, former governor Mitt Romney, is at heart an old-fashioned east coast liberal Republican. If he is to mount a credible challenge to Mr Obama in two months' time, Mr Romney must abandon the sometimes extreme stances he adopted to win the Republic primaries last spring and tack back to the political centre.