Those who came to the Invesco Field on Thursday witnessed something they are unlikely ever to forget. Barack Obama gave an electrifying speech that silences—for the moment at least—doubts in the Democratic party that they have backed the right candidate. He commanded this vast sports stadium with calm authority, there were no false notes, and the attention of his audience never wavered. His listeners were enthralled, and they left believing they will win in November. After this, they were asking, how could the country fail to elect their man president?

The event started slowly, with enormous lines at security, a dreary succession of second-rate speakers, and a clutch of by-the-numbers political videos. Al Gore, Sheryl Crow, and Stevie Wonder raised the standard only a little, with dull renditions of their greatest hits, and the thought that this entire mega-production was going to backfire was impossible to suppress. Who in the world thought that the Greek temple stage-set was right? If the designer’s brief had been ”low-budget hubris”, it worked; by any other standard it was a calamity. With the Republicans calling Mr Obama a vapid celebrity, this was outright self-parody. Yet none of it mattered when Mr Obama started to speak.