Where does ‘when push comes to shove’ really come from?

‘When push comes to shove’ means when you get down to something, when a subject or situation is stripped down to essentials, when the point is reached at which a commitment must be made.

No one seems to be exactly certain where this phrase actually originated, although there are a lot of interesting theories flying around the Internet. A couple of my favourites:

It originates from the game of rugby, where pushing and shoving is a vital skill. (This origin appears to have the most votes.)

Terry Pratchett, in Thief of Time, hints to the phrase coming from midwifery (Nanny Ogg).

It’s also been featured in songs, notably Grateful Dead ‘When Push comes to Shove‘, and Van Halen ‘Fair Warning –  Push Come to Shove‘.

Examples of ‘when push comes to shove’:

If push comes to shove, I doubt he’s got the guts for it.

Governments may encourage gender equality, but when push comes to shove, they’ll follow the money.

I’ve heard it used reasonably often on both sides of the Atlantic. While it’s definitely a colloquialism, it’s one that’s now been around so long that it wouldn’t be out of place in a range of settings.

Could it be adapted for use in a fantasy or sci-fi scenario? I can’t imagine why not; the phrase itself evokes vivid imagery, so it could be inserted as-is into a lot of world-building without flagging itself as an anachronism. Given the (probable) sporting origins of the phrase, it could be equally easily adapted to a pastime invented as part of your world-building.

What is etymology, and why are you excavating it?

Etymology is like the archeology of a language (definition: the study of the origin of words and the way in which their meanings have changed throughout history).