What did the president know, and when did he know it? Such was demanded of Richard Nixon, who resigned 40 years ago next month. In no sense can President Barack Obama be morally compared with the man who brought us Watergate. He is neither a crook nor a liar.

But Mr Obama shares one problem that could cripple what remains of his presidency – most people no longer trust him. The sentiment spans foreign allies as well as domestic critics. When trust goes, respect is seldom far behind.

The most surprising example is Germany. It was in Berlin in 2008 that then Senator Obama unveiled his global promise – an America that could once again be trusted. Germans no longer believe it. In the wake of the “friendly spying” ring allegations, less than 40 per cent of Germans consider the US a trustworthy partner, according to one survey.