Among conservatives the dropoff has been especially sharp: just 45 per cent view Francis favourably today as opposed to 72 per cent a year ago.

“This decline may be attributable to the Pope’s denouncing of ‘the idolatry of money’ and attributing climate change partially to human activity, along with his passionate focus on income inequality — all issues that are at odds with many conservatives’ beliefs,” wrote Gallup analyst Art Swift.

But liberal fervour for the Argentine Pope, who was elected to great acclaim in March 2013, has also cooled, dropping an average of 14 points.

Some observers have predicted that many who embraced the Pope’s candour and his views on a range of social justice issues would temper their ardor as they realized he would not change Church teachings on hot-button issues like abortion or contraception or gay marriage.

The decline comes just as American Catholics are set to welcome the Pope in September for his first visit to the United States. It essentially returns Francis to approval levels he had in the first months after his election.

The decline does appears to be relatively recent, and swift: a Pew Research Centre survey from last February showed Francis’ approval rating among all Americans at 70 per cent, and at a remarkable 90 per cent among all Catholics. That number had been steadily increasing.