You know that British politicians are quietly confident or uncertain when they turn to British history for support.
Mr Cameron was very definitely in one of those moods when he brought victories over the Spanish Armada in 1588; the battles of Blenheim in 1704 and Waterloo in 1815; the two World Wars, and the fall of the Berlin Wall to support his case for staying in the EU.
He made these references at a speech in the British Museum, London, the place where he will be remembered forever for making the right or wrong judgement about what future the British want.
If he was confident of winning the in-out UK referendum on June 23, he quoted these battles as examples of Britain being on the right side of European history.
If he was preparing for the defeat of a Brexit vote, he was lined up with the image of a plucky Britain standing along alone.
He knows that public support for remain or leave the EU is equal at 50%.