Four, and possibly five, of the last seven US presidents have been left-handed. (The “possibly” is because Ronald Reagan, while said to be a lefty, signed with his right.) But none of the other left-handed presidents had Mr Obama's (and my) tortured writing posture.

Google Images shows Gerald Ford and Bill Clinton writing with their left wrists straight, pens aimed back over their shoulders, just as right-handers do. George Bush the Elder curls his left writing hand very slightly. Only Mr Obama writes “upside down”.

Most left-handers who write this way say it is because we learnt to write in ink – and the “hooked” style meant we could avoid smudging. I suspect this is only part of the reason. Those, such as Mr Ford and Mr Clinton, who position their pens below their writing, rather than above it, avoid smudging too.