WHATEVER the virtues of the candidate, Mitt Romney's choice of the young, free market evangelist, Congressman Paul Ryan, as his running mate has brought the campaign to life.
Without a fresh face, it was in danger of becoming a battle of negatives in which the Republicans concentrated on the economic failings of the Obama administration and the Democrats tried to turn it back on the limitations and incoherence of Mitt Romney.
The grassroots activists of the Republican Party, of course, are delighted that a man of their own instinctive beliefs should be on the ticket. But the Democrats seem equally gleeful that, by picking a clear fiscal radical, their opponents are moving the debate on to the solid ground of policy alternatives.
They are right to see the advantages of getting the debate away from the area of Obama's record. But they would be well advised not to underestimate the benefits that Mr Romney's vice-presidential choice might bring to their opponents.
A Washington professional, he lacks broad experience of life outside politics and has made his name more as a policy wonk than a populist. But he has an easy manner with people and a gift for presenting economic issues in simple terms of American values and optimism.
For the outside world, as for many within America, that makes Mr Romney's decision to commit himself to right-wing policies worrying. At a time of faltering recovery in the world's largest economy, we can ill afford a lurch back to the contraction and the social strains that heavy cuts in public expenditure would bring. If nothing else Mr Romney's appointment puts policy back where it belongs, centre stage. It is now up to the Democrats to make clear the advantages of a different, more liberal and more internationalist approach.